WORK, ENERGY & POWER

Choose the FALSE statements about WORK

• Work is scalar quantity.

• Work is a product of force and the displacement of an object in the direction of force.

• Component of force is perpendicular to the direction of the motion.

• The unit of work is Newton-meter (Nm) or Joule (J).

A boy climbs a pole and stops at 4 meters height. If the mass of the boy is 60 kg, calculate the work done by the boy while climbing the pole.

• 2354.4 J

• 3254.4 J

• 2534.4 J

• 3524.4 J

If 1450 J of work is used to lift a box vertically to 25 m above the ground. Calculate the weight of the box.

• 58 N

• 5.8 kg

• 58 kg

• 5.8 N

Ahmad is walking with a constant speed of 6 m/s. What is Ahmad's kinetic energy, if Ahmad has a mass of 62 kg.

• 1116 J

• 186 J

• 2232 J

• 111.6 J

Potential energy is the energy possessed by an object due to its___

• position

• speed

• direction

• motion

Kinetic energy is the energy possessed by an object due to its___

• direction

• motion

• position

• location

Choose TRUE statement about principles of conservation of energy.

• Energy can be created but cannot be destroyed, and energy can transform from one form to another.

• Energy cannot be created but can be destroyed, and energy can transform from one form to another.

• Energy cannot be created, cannot be destroyed, but energy can transform from one form to another.

• Energy can be created, can be destroyed, and energy can transform from one form to another.

An apple with a mass of 0.025 kg falls from a tree. The high is 4 m high from the ground. Find the potential energy while the apple is still on the tree.

(Given: gravity, g = 9.81 m/s²)

• 0.981 J

• 9.81 J

• 98.1 J

• 981 J

Which one is the definition of POWER?

• The ability to do work.

• The rate of energy used.

• The rate of work done.

• The ability to produced energy.

Given :

Power, P = 28 Watts

Work done, W = 3500 J

Calculate the time, t.

• 125 s

• 125 min

• 12.5 s

• 12.5 min