What is the equation for momentum?
Did this page help you?
Syllabus Edition
First teaching 2014
Last exams 2024
What is the equation for momentum?
Did this page help you?
A tennis ball is thrown at a wall and then bounces off.
Which row states the correct directions for the velocity, v, before and after hitting the wall?
Before collision |
After collision |
|
A. | − | − |
B. | − | + |
C. | + | − |
D. | + | + |
Did this page help you?
A car drives into a wall. The change in momentum is 17 000 kg ms−1 and the time of impact is 0.1 seconds.
What is the force acting on the car as a result of the collision?
17 000 N
1 700 000 N
170 000 N
1700 N
Did this page help you?
Which of the following is the correct equation for impulse?
Did this page help you?
Which feature on a force-time graph represents the impulse?
Gradient
y-intercept
Area
x-intercept
Did this page help you?
Before a collision object A is stationary and object B is travelling at 1 ms−1 .
What is the correct symbol and value for the initial velocity of object A?
uB = 0
uA = 0
vA = 0
uA = 1
Did this page help you?
What is the definition of an external force?
Forces that act on a system from outside of it
Forces exchanged by the particles in a system
Every action has an equal and opposite reaction
The rate of change of momentum on a body
Did this page help you?
What is the definition of an inelastic collision?
A collision where kinetic energy is conserved
A collision where the momentum is conserved
A collision where both objects are stationary after the collision
A collision where kinetic energy is not conserved
Did this page help you?
What is the main purpose of the crumple zone in a car?
To decrease the contact time over which a collision occurs.
To increase the contact time over which a collision occurs.
To reduce the mass of the car involved in the collision.
To reduce damage to the rest of the car in a collision.
Did this page help you?
What type of collision are explosions?
Elastic
Conserved
Inelastic
Impulsive
Did this page help you?
A force acts on a mass of 5.0 kg and it is initially at rest.
What is the time taken for the mass to reach an acceleration of 2 m s-2?
2.50 s
2.20 s
2.25 s
2.00 s
Did this page help you?
A body of mass 3M at rest explodes into two pieces of mass 2M and M.
What is the ratio and ?
|
||
A. |
-1 |
|
B. |
1 |
-1 |
C. |
2 |
|
D. |
-2 |
Did this page help you?
Which of the following is an elastic collision?
A ball dropped from a height and bouncing up to a lower height
Two railway trucks colliding and they link together
Two gas molecules collide and a bond is formed between them
Two gas molecules collide and then travel perpendicular to each other
Did this page help you?
A ball of mass m travels horizontally and strikes a vertical wall with a speed of vinitial ms-1. It then rebounds horizontally at speed vfinal ms-1. The ball is in contact with the wall for time Δt.
What is vfinal if the ball rebounds after an impulse of magnitude I?
A. |
vfinal = |
B. |
vfinal = |
C. |
vfinal = |
D. |
vfinal = |
Did this page help you?
A stone of mass 0.5 kg is thrown with an initial speed of 10 m s-1 at an angle θ to the vertical. P is the highest point of the motion and air resistance is negligible.
What is the momentum of the stone at P?
5 sin θ
5
5 cos θ
0
Did this page help you?
A truck T moving horizontally collides with an identical truck S that is at rest.
T strikes S with speed 2v.
What is a possible outcome of the collision?
Did this page help you?
A ball of mass m strikes a vertical wall with a speed v at an angle of θ to the wall. The ball rebounds at the same speed and angle in time t. What is the magnitude of the impulse on the wall?
zero
2mv
2mv sin θ
2mv cos θ
Did this page help you?
A ball of mass 4.0 kg, initially at rest, is acted on by a force F which varies with t.
What is the velocity of the ball after 14 s?
7 m s-1
56 m s-1
14 m s-1
28 m s-1
Did this page help you?
Which of the following is true for momentum and impulse?
Momentum is conserved in an inelastic collision
Impulse is the momentum
The direction in which an object is travelling in doesn’t affect its impulse
A heavier object always experiences a greater impulse than a lighter one
Did this page help you?
Two balls m and 2m collide elastically with speeds v and 2v respectively. After the collision, they both move in opposite directions.
What speed does the 2m ball move with after the collision?
A. |
v |
B. |
v |
C. |
v |
D. |
v |
Did this page help you?
Water is ejected from the nozzle of a hose through a hole of a diameter 2 cm. The water leaves the nozzle of the hose with a velocity of 25 cm s–1 and travels horizontally towards a wall, as shown below.
After colliding with the wall the water has zero velocity. Water has a density of 1 g cm–3.
What is the force exerted by the water on the wall?
625π g cm s-2
25π g cm s-2
N
2500π g cm s-2
Did this page help you?
A ball of mass 0.60 kg is kicked off a cliff with a horizontal velocity of 3.0 m s–1. It follows the path of a projectile shown below and lands with a velocity of 4.0 m s–1 at an angle of 30o to the ground. Air resistance is negligible during the flight.
What is the magnitude of the change in momentum of the ball between the top of the cliff and the ground below?
You may need to use the following trigonometric values to help you:
cos(30) =
sin(30) =
N s
0.6 N s
2 N s
1.2 N s
Did this page help you?
A BB gun fires 4 g ball bearings at a rate of 100 balls per minute. The balls leave the BB gun at a velocity of 20 m s–1 and strike a fixed steel block. The balls rebound off the block with the same velocity as they were fired.
What is the average force exerted on the steel container?
16 N
N
N
N
Did this page help you?
Two trolleys, X and Y, are connected by an elastic cord, of negligible mass, as shown below. Trolley X is twice the mass of trolley Y.
The two trolleys are pulled apart so that the elastic cord is stretched. The trolleys are then released at the same time and move towards each other. The trolleys stick together on impact.
Just before the trolleys collide, the speed of trolley X is 20 cm s–1.
What is the speed of the trolleys after they collide?
20 cm s−1
0 cm s−1
10 cm s−1
30 cm s−1
Did this page help you?
The diagram below shows a block of mass 2 kg sliding down a rough slope from rest against a constant friction force of 2.5 N.
Use the following assumptions to help you:
Acceleration due to free fall is 10 m s−2
cos(20) = 0.9
sin(20) = 0.3
What is the momentum of the block along the slope after 5 seconds?
7.75 kg m s−1
38.75 kg m s−1
77.5 kg m s−1
17.5 kg m s−1
Did this page help you?
A car of mass 3000 kg is travelling at 5 m s–1 when it collides with a wall and is brought to rest. The force-time graph of the impact is shown below.
What is the maximum force exerted on the car?
15 000 N
300 000 N
75 N
3000 N
Did this page help you?
The variation of the force, F, with time, t, acting on a mass of 160 g is shown on the graph below.
The velocity of the body at t = 10 ms is 5 m s–1.
What is the velocity of the body at t = 35 ms?
30 m s−1
m s−1
m s−1
m s−1
Did this page help you?
Particle P has a mass m and is moving towards a stationary particle, Q, of mass M. P is travelling with a velocity of u before colliding head on with particle Q. The collision between the particles is elastic.
What is the velocity of particle Q after the collision?
u
2mu
Did this page help you?
Two spheres approach each other along the same straight line. Their speeds are u1 and u2 before collision, and v1 and v2 after collision, in the directions shown below
Which equation is correct if the collision is perfectly elastic?
u1 – u2 = v2 – v1
u1 – u2 = v2 + v1
u1 + u2 = v2 + v1
u1 + u2 = v2 – v1
Did this page help you?