# Worksheet: Kinetic Energy

Q1:

Find the kinetic energy of a body of mass 4 kg moving at 36 m/s. Express your answer in ergs.

• A erg
• B erg
• C 2 592 erg
• D erg
• E erg

Q2:

A body of mass 28 kg was moving at 28 m/s when a force started acting on it. As a result, its speed became 7 m/s. Find the change in kinetic energy of the body. Take .

Q3:

Given that the kinetic energy of a moving bullet of mass kg, at a certain instant, was 7 000 joules, determine its speed.

Q4:

A cannon fired a shell of mass 16 kg at 285 m/s towards a tank that was moving at 72 km/h in a straight line directly towards the cannon. Determine the kinetic energy of the shell relative to the motion of the tank.

Q5:

A particle of mass 150 g was projected at 13 m/s across a horizontal plane. It decelerated uniformly at 2 m/s2. Find the change in its kinetic energy in the first 4 seconds of motion.

Q6:

A force of 150 g-wt was acting on a body of mass 189 g that was resting on a smooth horizontal plane. Determine the body’s kinetic energy 6 seconds after the force started acting on it. Take .

Q7:

A body of mass 1.7 kg is projected vertically upward at 13.7 m/s from the surface of the Earth. Find its kinetic energy 1 second after it was projected. Consider the acceleration due to gravity to be 9.8 m/s2.

• A 25.86 joules
• B 159.54 joules
• C 319.07 joules
• D 12.93 joules
• E 469.41 joules

Q8:

A body of mass 8 kg was projected vertically upward at 34.3 m/s. After a certain time , its kinetic energy became 198.45 joules. Find . Take .

• A or
• B or
• C
• D or

Q9:

A body of mass 1 kg was projected at 2 m/s up the line greatest slope of a smooth plane inclined to the horizontal at an angle whose sine is . Taking , determine the change in the body’s kinetic energy in the first 5 seconds of motion.

Q10:

A body of mass 750 g was projected at 450 cm/s up the line of greatest slope of a smooth plane inclined at to the horizontal. Find its kinetic energy 4 seconds after it was projected.

• A ergs
• B ergs
• C ergs
• D ergs
• E ergs

Q11:

A smooth plane is inclined at an angle to the horizontal, where . A body of mass 8 kg is projected at 15 m/s up a line of greatest slope of a plane. Determine the change in the body’s kinetic energy in the first 5 seconds of its motion. Take .

Q12:

A train of mass 56 tonnes was moving on a straight section of horizontal track. The resistance to the train’s motion was proportional to the square of its speed. Given that the force generated by the train’s engine was 700 kg-wt, and the resistance to its motion was 8 kg-wt per tonne of its mass when its speed was 57.6 km/h, determine the train’s maximum possible kinetic energy.

• A joules
• B joules
• C joules
• D joules
• E joules

Q13:

A body of mass 500 g is moving at a constant velocity , where and are two perpendicular unit vectors. Find its kinetic energy.

• A
1 250
ergs
• B
6 500
ergs
• C ergs
• D
3 250
ergs
• E ergs

Q14:

A body is moving at a constant velocity , where and are two perpendicular unit vectors. Given that the kinetic energy of the body is 4.8 joules, find the mass of the body.

Q15:

A particle is moving in a straight line. At time seconds, where , the particle’s displacement relative to a fixed point is given by , where and are two perpendicular unit vectors. Given that the kinetic energy of the body at is 30 joules, determine the body’s mass.

Q16:

A body of mass 1 kg is moving in a straight line. After time seconds, where , the body’s displacement relative to a fixed point is given by , where is a fixed unit vector. Find the kinetic energy of the body, 3 seconds after it started moving.

Q17:

A body of mass 3 kg is moving across a plane. At time seconds, where , the body’s position vector relative to a fixed point is given by , where is a fixed unit vector. Given that at , the kinetic energy of the body is 54 joules, find all the possible values of .

• A
• B
• C or
• D or

Q18:

A body of mass 2 kg is moving under the action of three forces: , , and , where and are two perpendicular unit vectors. After time seconds, where , the body’s displacement relative to a fixed point is given by . Find the body’s kinetic energy 2 seconds after the forces started acting.