IB Energy in Mechanics

A car takes 20 minutes to climb a hill at constant speed. The mass of the car is 1200 kg and the car gains gravitational potential energy at a rate of 6.0 kW. Take the acceleration of gravity to be 10 ms⁻². What is the height of the hill?

• 0.6m

• 10m

• 600m

• 6000m

A projectile is launched upwards at an angle θ to the horizontal with an initial momentum p₀ and an initial energy E₀. Air resistance is negligible. What are the momentum and total energy of the projectile at the highest point of the motion?

• A

• B

• C

• D

The graph shows the variation with distance of a horizontal force acting on an object. The object, initially at rest, moves horizontally through a distance of 50m.

A constant frictional force of 2 N opposes the motion. What is the final kinetic energy of the object after it has moved 50 m?

• 100 J

• 500 J

• 600 J

• 1100 J

A force acts on an object of mass 40 kg. The graph shows how the acceleration a of the object varies with its displacement d.

What is the work done by the force on the object?

• 50 J

• 2000 J

• 2400 J

• 3200 J

A student of weight 600N climbs a vertical ladder 6.0m tall in a time of 8.0s. What is the power developed by the student against gravity?

• 22W

• 45 W

• 220 W

• 450 W

An object of mass 2kg is thrown vertically downwards with an initial kinetic energy of 100J. What is the distance fallen by the object at the instant when its kinetic energy has doubled?

• 2.5 m

• 5.0 m

• 10 m

• 14 m