Conceptual Physics Mid-Term Review Packet
Ch.2 Linear Motion
1. What are Vectors and what are scalars. Give examples.
Vectors have magnitude and direction. Scalars have only magnitude.
2. What is motion usually measured relative to?
To the Earth.
3. Define Speed? What are its units?
Speed is how fast an object is moving. It is distance over time and is measured in m/s, km/h,
miles/h etc.
4. What is average speed? How is it measured?
Average speed is total distance over total time. It is measured in the same units as speed.
5. Define Velocity. What are its units?
Velocity is rate of change of displacement. It is a vector and has both magnitude and
direction. Example. 10 km/h due North, 30 m/s due South.
6. What is instantaneous speed? Does your speedometer refer to average or
instantaneous speed?
7. If an object covers the same distance of 10 m every second, what are its velocity and
acceleration?
v = 10 m/s; a = 0 m/s2
8. What are the speed and distance of a freely falling object which is dropped from rest
After 1s, 2s & 5s. g = 10 m/s2
t
v = gt
d = ½ g.t2
1s
10 m/s
5m
2s
20 m/s
20 m
5s
50 m/s
125 m
9. What are the instantaneous velocity and acceleration of a ball thrown straight up, at
the top of its path
v = 0 m/s
a = 10 m/s2
10. In the absence of air resistance which will reach the ground first, a tennis ball or a
bowling ball.
They will reach at the same time.
11. If a ball is thrown up at a speed of 40 m/s, how much time will it take to reach the
maximum height ? In how much time will it hit the ground. g = 10 m/s2
t = (0-40) /10 = 4 s, it will take twice that or 8 s to reach the ground.
12. How do you measure hang time for an athlete who jumped 1 m high?
d = 1 m = ½ g.t2
or t2 = 1/5 s or t = (1/5)1/2
13. What is the maximum height jumped by an athlete who has a hang time of 0.8 s.
d = ½ g.t2, t is total hang time, so time to reach maximum height is 0.4 s, so d = 0.8 m
Ch.3 Projectile Motion
14. How do you find the components of a vector? How do you find resultant of two vectors?
Refer to worksheets and notes given.
15. What is the resultant of two vectors, each of length 100 units and at right angles to the other
R = (A2 + B2)1/2 = (1002 + 1002)1/2 = 140 units
16. What is the ground speed of a plane which is traveling at 80 km/h, if it encounters
(a) tailwind of 10 km/h (b) headwind of 15 km/h (c) 60 km/h wind at right angles to it
(a) 80 + 10 = 90 km/h (b) 80 – 15 = 65 km/h (c) (602 + 802)1/2 = 100 km/h
17. What are the horizontal and vertical forces acting on a projectile in the absence of air
resistance? Does the above projectile have horizontal or vertical acceleration during flight?
There is no horizontal force and horizontal acceleration is zero. The vertical force acting on
it is the gravitational force and its vertical acceleration is g = 10 m/s2 at all times.
18. Are the horizontal and vertical components of a projectile dependent on each other? For a
projectile launched at some angle, does the ball have horizontal or vertical velocity at the top
of its path?
The H & V components are entirely independent of each other. The ball has zero vertical
velocity at the top, but its horizontal velocity is not zero and is the same velocity through out
its flight.
19. What is the launch angle for a projectile to travel the (a) farther horizontal distance and the
(b) greatest vertical height ?
(a) 450
(b) 900
Ch. 4 – Ch.6 Newton’s Laws
20. State Newton’s three laws of motion
Refer to your textbook.
21. Define mass, weight & volume. What are their units?
Refer to your textbook.
22. Would an object of mass 20 kg have greater weight on the Moon, Earth or Jupiter?
Jupiter, as it has the greatest value of g. It would weigh the least on the Moon.
23. If an object weighs 400 N, what is its mass?
Mass = Weight / g = 400 / 10 = 40 kg
24. What happens when a net force acts on an object?
Its velocity or state of rest changes. The object accelerates.
25. If no net force acts on an object, what is necessarily zero (a) Velocity (b) Acceleration
Acceleration is necessarily zero if no net force acts on an object.
26. If you hang from a clothesline when is the tension in the line greater, if the line is strung
(a) Vertically (b) Horizontally
Tension is greater when the line is strung horizontally.
27. What is the gravitational force acting on an object of 1 kg mass. g = 10 m/s2
F = Weight = 1 kg x 10 m/s2 = 10 N
28. If the 1 kg object is thrown up, does the net force change during its flight? No
29. The acceleration of an object acted upon by a force is directly proportional to the applied
force and inversely proportional to the mass.
30. Based on Newton’s 2nd law, if mass of an object doubles, for the same applied force, what
happens to its acceleration?
The acceleration reduces to half of its value.
31. For the same mass if the force is doubled, what happens to its acceleration?
The acceleration doubles.
32. What is terminal velocity? What is the acceleration of an object at terminal velocity?
Acceleration is zero for an object that has reached terminal velocity.
33. Define Pressure. What are the units?
Pressure is force applied per unit area. It is measured in Pascal.
34. Is the force of gravity the same for 1 kg and 10 kg object? Is g the same for both?
Force of gravity is greater for a 10 kg object. But g is the same for both.
35. A cannonball is fired. Is the force acting on the ball and the cannon the same? Are
the magnitudes of their acceleration equal?
Yes, the forces are the same, but the acceleration of the ball is much greater than the cannon
due to its smaller mass.
36. If the Earth’s gravitational pull on a falling apple is the Action force, what is the Reaction
force? Are they equal?
The Reaction force is the Apple pulling on the apple. Yes, they are equal and opposite.
37. Do Action and Reaction force act on the same object.
No, A-R forces act in pairs. They act on different objects.
38. If a horse drawn cart is to move faster, should the horse push harder on the ground or pull
harder on the cart ?
It should push harder on the ground.
Ch. 8. Energy
39. What are the different forms of mechanical energy? Refer to textbook
40. Define Potential and Kinetic Energy. What are the units? Refer to textbook.
41. Can an object at rest have Potential or Kinetic Energy?
It can only have potential energy.
42. Define Power. What are its units?
Power is the rate of doing work. Its units are Watt.
43. What is the law of conservation of energy? Refer to handouts & textbook.
44. How is mechanical energy converted from kinetic to potential energy in an ideal simple
Pendulum? At which position does a pendulum have
(a) Max K.E (b) Zero K.E (c) Max P.E (d) Zero P.E
(a) & (d) At the middle
(b) & (c) At the ends of the swing