Questions
Newton’s 1st Law
1.
State Newton’s 1st Law of motion.
2.
Which of the following situations does Newton’s 1st Law apply? Explain your answers.
Situation
1st Law ?
Explanation
In outer space, gravitational forces are negligible and
A rocket travels in outer space.
Engines are off.
Yes
there is no air resistance. Thus, there are no forces
acting on the rocket and it will travel at a constant
velocity, in a straight line.
A body moves within a car at a
constant velocity, which then stops
suddenly. The body within the car
is not wearing a seatbelt and is
thrown forward.
A ice-skater glides along the ice at
the same speed in a straight line
A book lays motionless on a table.
The book exerts a force on the
table and the table exerts an equal
and opposite force on the book.
3.
The net force acting on a body is zero. Which of the following quantities must also have zero magnitude for this body?
A.
Momentum
B.
Velocity
C.
Speed
D.
Acceleration
Questions
Newton’s 2nd Law
1.
State Newton’s 2nd Law of motion.
2.
A trolley of mass 1.5 kg is pulled along a horizontal table by a force of 5.0N. The frictional force acting on the trolley is
0.50N. The acceleration of the trolley is:
3.
A.
0.30m s −2
B.
0.33m s −2
C.
3.0m s −2
D.
3.3m s −2
A crane raises a load by a cable. If the total mass of the load is 1500kg and the tension in the cable is 23,500N,
calculate the upwards acceleration of the load.
4.
An astronaut has a mass of 80kg . His weight on the moon is 128N . The astronaut holds a camera of mass 1.5kg and is
allowed to fall freely on the planet. Calculate its acceleration.
Questions Continued
Newton’s 2nd Law
5.
A car of mass 800kg accelerates along a road. It has a thrust of 700N and a drag force of 100N. The car is originally at
rest. After 10 seconds, the driver removes his foot from the thrust pedal. The thrust is now 0N.
a)
Calculate the acceleration of the car in the first 10 seconds.
b)
Calculate the maximum speed of the car.
c)
How long would the car take to come to rest?
d)
Plot an accurate velocity-time graph of the motion. Include numerical values on both axes.
Questions
Newton’s 3rd Law
1.
State Newton’s 3rd Law of motion.
2.
State the Newton’s 3rd law pair of forces in each situation below. The first one is done for you.
a)
Opposing electrostatic charges
The negative charge exerts an electrostatic force on the positive charge, and the positive
charge exerts an equal and opposite electrostatic force on the negative charge.
b)
Car standing stationary on road
c)
The Moon orbiting the Earth.