Career Vision Physics Classess
By : Er S K Chaudhary
Work Power Energy Problem
1. A body of mass 5 kg is placed at the origin, and can move only on the x-axis. A force of
10 N is acting on it in a direction making an angle of 60 with the x-axis and displaces it
along the x axis by 4 metres. The work done by the force is
2. A 10 kg satellite completes one revolution around the earth at a hei ght of 100 km in
108minutes. The work done by the gravitational force of earth will be
3. A position dependent force F (7-2x+3x2) acts on a small abject of mass 2 kg to displace
it from x = 0 to x = 5m . The work done in joule is
4. A particle moves under the effect of a force F = Cx from x = 0 to x = x1. The work done
in the process is Work done in time t on a body of mass m which is accelerated from
rest to a speed v in time 1 t as a function of time t is given by
5. A particle of mass 0.01 kg travels along a curve with velocity given by 4ˆi + 16kˆ m/s.
After sometime, its velocity becomes 8 i+ 20 j m/s due to the action of a conservative
force. The work done on particle during this interval of time is
6. A running man has half the kinetic energy of that of a boy of half of his mass. The man
speeds up by 1 m/s so as to have same K.E. as that of boy. The original speed of the
man will be
7. If the momentum of a body increases by 0.01%, its kinetic energy will increase by
8. A body of mass 5 kg is moving with a momentum of 10 kg-m/s. A force of 0.2 N acts on
it in the direction of motion of the body for 10 seconds. The increase in its kinetic
energy is
9. Two masses of 1g and 9g are moving with equal kinetic energies. The ratio of the
magnitudes of their respective linear momenta is
10 A 300 g mass has a velocity of (3ˆi + 4ˆj)m/sec at a certain instant. What is its kinetic
energy
10. A vehicle is moving on a rough horizontal road with velocity v. The stopping
distance will be directly proportional to
11. A long spring is stretched by 2 cm, its potential energy is U. If the spring is stretched
by 10 cm, the potential energy stored in it will be
12. A spring of spring constant 5x10 3 N /m is stretched initially by 5 cm from the unstretched position. Then the work required to stretch it further by another 5 cm is
13. Two springs of spring constants 1500 N /m and 3000 N /m respectively are stretched
with the same force. They will have potential energy in the ratio
14. The work done in pulling up a block of wood weighing 2kN for a length of 10 m on a
smooth plane inclined at an angle of o 15 with the horizontal is (sin 15o = 0.259)
15. If g is the acceleration due to gravity on the earth’s surface, the gain in the potential
energy of
16. an abject of mass m raised from the surface of earth to a height equal to the radius
of the earth R, is
17. A body is falling under gravity. When it loses a gravitational potential energy by U, its
speed is v. The mass of the body shall be
18. A boy is sitting on a swing at a maximum height of 5m above the ground. When the
swing passes through the mean position which is 2m above the ground its velocity is
approximately
19. If we throw a body upwards with velocity of m/s at what height its kinetic energy
reduces to half of the initial value ?
20. A 2kg block is dropped from a height of 0.4 m on a spring of force constant K = 1960
N/m . The maximum compression of the spring is
21. A stone projected vertically upwards from the ground reaches a maximum height h.
When it is at a height 3h/4 ,the ratio of its kinetic and potential energies is
22. A pump motor is used to deliver water at a certain rate from a given pipe. To obtain
twice as much water from the same pipe in the same time, power of the motor has to be
increased to
23. A force applied by an engine of a train of mass 2.05x10 6kg changes its velocity from 5
m/s to 25 m/s in 5 minutes. The power of the engine is
24. From a water fall, water is falling at the rate of 100 kg/s on the blades of turbine. If the
height of the fall is 100m then the power delivered to the turbine is approximately equal
25. A particle moves with a velocity v = 5i-3 j + 6 k m/s under the influence of a constant
force F = 10ˆi + 10ˆj + 20kˆ N The instantaneous power applied to the particle is
26. Two men with weights in the ratio 5 : 3 run up a staircase in times in the ratio 11 : 9.
The ratio of power of first to that of second is
27. A constant force F is applied on a body. The power (P) generated is related to the time
elapsed (t) as
28. A body of mass 5 kg is moving with a momentum of 10 kg-m/s. A force of 0.2 N acts on
it in the direction of motion of the body for 10 seconds. The increase in its kinetic energy is
29. If the momentum of a body is increased by 100 %, then the percentage increase in the
kinetic energy is
30. A box of mass 1 kg is pulled on a horizontal plane of length 1 m by a force of 8 N then it
is raised vertically to a height of 2m, the net work done is
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Circular Motion
1. A wheel covers a distance of 9.5 km in 2000 revolutions. The diameter of the wheel
is
2. A particle completes 1.5 revolutions in a circular path of radius 2 cm. The angular
displacement of the particle will be – (in radian)
3. A scooter is going round a circular road of radius 100 m at a speed of 10 m/s. The
angular speed of the scooter will be
4. The ratio of angular velocity of rotation of minute hand of a clock with the angular
velocity of rotation of the earth about its own axis is
5. A body is whirled in a horizontal circle of radius 20 cm. It has angular velocity of
10 rad/s. What is its linear velocity at any point on circular path
6. The linear velocity of a point on the equator is nearly (radius of the earth is 6400
km)
7. A particle moves along a circle with a uniform speed v. After it has made an angle
of 60o its speed will be
8. A particle comes round circle of radius 1 m once. The time taken by it is 10 sec. The
average velocity of motion is
9. Two particles of mass M and m are moving in a circle of radii R and r. If their time periods are same, what will be the ratio of their linear velocities
10. The linear acceleration of a car is 10m/s2. If the wheels of the car have a
diameter of 1m, the angular acceleration of the wheels will be
11. The angular speed of a motor increases from 600 rpm to 1200 rpm in 10 s. What
is the angular acceleration of the motor
12. If a cycle wheel of radius 4 m completes one revolution in two seconds. Then
acceleration of the cycle will be
13. A stone is tied to one end of a spring 50 cm long is whirled in a horizontal circle
with a constant speed. If the stone makes 10 revolutions in 20 s, what is the
magnitude of acceleration of the stone
14. A particle moves with a constant speed v along a circular path of radius r and
completes the circle in timeT. What is the acceleration of the particle
15. Two cars going round curve with speeds one at 90 km/h and other at 15 km/h.
Each car experiences same acceleration. The radii of curves are in the ratio of
16. A wheel of radius 0.20m is accelerated from rest with an angular acceleration of
1 rad / s2 After a rotation of o 90 the radial acceleration of a particle on its rim will
be
17. a stone of mass 1 kg tied to the end of a string of length 1 m, is whirled in a
horizontal circle with a uniform angular velocity of 2 rad/s. The tension of the
string is (in N)
18. If mass speed and radius of rotation of a body moving in a circular path are all
increased by 50%, the necessary force required to maintain the body moving in the
circular path will have to be increased by
19. A motor cycle driver doubles its velocity when he is having a turn. The force
exerted outwardly will be
20. A particle does uniform circular motion in a horizontal plane. The radius of the
circle is 20 cm. The centripetal force acting on the particle is 10 N. It’s kinetic
energy is
21. A body of mass 100 g is rotating in a circular path of radius r with constant
velocity. The work done in one complete revolution is
22. Find the maximum velocity for overturn for a car moved on a circular track of
radius 100m The coefficient of friction between the road and tyre is 0.2
23. The coefficient of friction between the tyres and the road is 0.25. The maximum
speed with which a car can be driven round a curve of radius 40 m with skidding is
24. A boy on a cycle pedals around a circle of 20 metres radius at a speed of 20
metres/sec. The combined mass of the boy and the cycle is 90kg . The angle that
the cycle makes with the vertical so that it may not fall is
25. If a cyclist moving with a speed of 4.9 m / s on a level road can take a sharp
circular turn of radius 4m , then coefficient of friction between the cycle tyres and
road is
26. For traffic moving at 60 km / hr along a circular track of radius 0.1 km , the
correct angle of banking is
27. The radius of curvature of a road at a certain turn is 50m . The width of the road
is 10m and its outer edge is 1.5m higher than the inner edge. The safe speed for
such an inclination will be
28. Keeping the banking angle same to increase the maximum speed with which a
car can travel on a curved road by 10%, the radius of curvature of road has to be
changed from 20m to
29. The slope of the smooth banked horizontal road is p . If the radius of the curve be
r , the maximum velocity with which a car can negotiate the curve is given by
30. The road way bridge over a canal is in the form of an arc of a circle of radius 20 m
. What is the minimum speed with which a car can cross the bridge without leaving
contact with the ground at the highest point
31. The speed of a particle moving in a circle of radius 0.1m is v = 1.0t where t is
time in second. The resultant acceleration of the particle at t = 5s will be
32. A car is moving with speed 30 m/sec on a circular path of radius 500 m. Its speed
is increasing at the rate of 2m/sec 2. What is the acceleration of the car
33. The angular velocity of a particle is given by w= 1.5t-3t2 +2 the time when its
angular acceleration ceases to be zero will be
34. If the equation for the displacement of a particle moving on a circular path is
given by q =2 t 3+.5 , where q is in radians and t in seconds, then the angular
velocity of the particle after 2 sec from its start is
35. A particle is kept at rest at the top of a sphere of diameter 42m. When disturbed
slightly, it slides down. At what height h from the bottom, the particle will leave the
sphere
36. A bucket tied at the end of a 1.6 m long string is whirled in a vertical circle with constan t speed.
What should be the minimum speed so that the water from the bucket does not spill, when the
bucket is at the highest position
37. A can filled with water is revolved in a vertical circle of radius 4m and the water just does not
fall down. The time period of revolution will be
38. A particle is moving in a vertical circle. The tensions in the string when passing through two
positions at angles 30o and 60o from vertical (lowest position) are T1 and T2 respectively, Then
39. With what angular velocity should a 20 m long cord be rotated such that tension in it, while
reaching the highest point, is zero
40. A body of mass of 100 g is attached to a 1m long string and it is revolving in a vertical circle.
When the string makes an angle of o 60 with the vertical then its speed is 2 m / s . The tension in
the string at o angle = 60 will be
41. A force of 12 N gives an object an acceleration of 4 m/sec 2 . the force required to give it
an acceleration of 10m/sec 2 is
42. A body of mass 2 kg moving on horizontal surface with an initial velocity of 4 m/sec
comes to rest after 2 second . if one wants to keep this body moving on the surface with a
velocity 4m/sec , the force required is
43. A weight of 290 N and another of 200 N are suspended by a rope on either side of friction
less pulley . the acceleration of each block is
44. What force should be applied on 5 kg body so that it has a downwards acceleration
4m/sec2 ?
45. A certain force gives a 2 kg object an acceleration of .5m/sec2 . what acceleration would
the same force gives a 10 kg object ?
46. An 80 kg man stands on spring balance in an elevator . when it start to move the scale
reads 700N what is acceleration of elevator ?
47. A body of mass 1 kg is moving towards east with uniform speed of 2m/s . a force of 2N is
applied to it towards north the magnitude of displacement of the body 2 sec after the
force is applied , is ?
48. A body of mass 50kg acquires a speed of 20m/sec under a force of 100 N in t ime
49. The mass of an elevator is 400kg when tension in supporting cable is 48000N , the
acceleration of the elevator is ?
50. While launching a rocket of mass 10 4 kg , force of 10 6 N is applied for 10 sec the speed
attained by rocket at the end of 10 sec is
51. An elevator is moving vertically up with speed an acceleration “a” . the force exerted on
the floor by a passenger of mass m Is ?
52. Two mass 10 kg & 20 kg are connected by a mass less spring as shown . a force of 200N
acts on the 20 kg mass . at certain instant acceleration of the 10 kg mass is 12m/sec 2. The
acceleration of the 20 kg mass at instant is