Energy and Work Done Quiz

State whether each of the following statements is true or false. Then, correct any false statements.

Groups:

(a) True

,

(b) False

• Energy cannot be created or destroyed, only transformed.
• Solar energy is a renewable resource.
• Renewable energy sources are replenished naturally.
• Energy can be created but not destroyed.

• Whenever an object moves, work is done.

• Electric cars produce no emissions at all.

• Geothermal energy is derived from the Earth's internal heat.

• Crude oil, coal, and biofuels are renewable sources of energy.

Isaac throws a basketball into the air. At some point in the air, the basketball has 50 J of kinetic energy and 50 J of potential energy. How much total energy does the basketball have when:

(i) it has just left Isaac's hand;

(ii) it is about to touch the ground

(Assume that the effect of the basketball's friction with air can be ignored.)

• (i) 50 J

  (ii) 50 J

• (i) 100 J

  (ii) 100 J

• (i) 50 J

  (ii) 0 J

• (i) 0 J

  (ii) 50 J

Isaac throws a basketball into the air. At some point in the air, the basketball has 50 J of kinetic energy and 50 J of potential energy. Which of the following statement(s) about the basketball is/are true?

i. The basketball has maximum speed when it reaches its maximum height.

ii. The basketball has maximum kinetic energy just after it leaves Isaac's hand.

iii. The kinetic energy of the basketball is always equal to its potential energy.

• i and ii

• ii and iii

• ii only

• all the three statements are true

A ball is bouncing on the ground. Why does the ball not return to its original height?

• The ball loses energy by friction only.

• The ball's energy is converted into sound energy and heat.

• The ball loses kinetic energy and gains potential energy.

• The ball loses potential energy and gains kinetic energy.

Which of the following does not lead to a conversion of energy?

• Lifting a stack of books off a table.

• Pulling on a rope tied to a tree.

• Pushing a loaded wheelbarrow up a slope.

• Pushing oneself away from the wall of a swimming pool.