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Newton's Laws

See also the MC questions on momentum

Q1. The mass of fuel in a racing car decreases during a race.

As a result the lap time decreases.

Which of the following could explain this decrease?

A There is less friction on the race track.
B The maximum speed of the car has increased.
C The maximum acceleration and deceleration are greater.
D The engine is more efficient.

 

Q2. What is represented by the area under a force–displacement graph?

A
 rate of change of kinetic energy
B
change in momentum
C
work done
D
 acceleration

 

Q3. Which of the following is not a unit of power?

A
 N m s–1
B
 J s
C
 W
D
kg m2 s –3

 

Q4. In a test a 500 kg car travelling at 10 m s–1 hits a wall.

The front 0.30 m of the car crumples as the car is brought to rest.

What is the average force on the car during the impact?

A
 830 N
B
 7.5 kN
C
 8.3 kN
D
 83 kN

 

Q5. A rocket has a mass of 12,000 kg.

It accelerates vertically upwards from the surface of the Earth at 1.4 m s−2.

What is the thrust of the rocket?

A
 1.7 × 104 N
B
 1.0 × 105 N
C
 1.3 × 105 N
D
 1.6 × 105 N

 

Q6. What is a correct unit for the area under a force−time graph?

A
 N m
B
 kg m s−1
C
 kg m s−2
D
 N s−1

 

Q7. A mass of 2.5 kg is released from rest at X and slides down a ramp, of height 3.0 m, to point Y as shown.

When the mass reaches Y at the bottom of the ramp it has a velocity of 5.0 ms–1 .

What is the average frictional force between the mass and the ramp?

A
8.5 N
B
10.6 N
C
14.7 N
D
24.5 N

 

Q8. Two bodies of different masses undergo an elastic collision in the absence of any external force.

Which row gives the effect on the total kinetic energy of the masses and the magnitudes of the forces exerted on the masses during the collision?

Total kinetic energy
Magnitudes of forces
A
remains unchanged
same on both masses
B
remains unchanged
greater on the smaller mass
C
decreases
same on both masses
D
decreases
greater on the smaller mass