Write the letter of the correct answer on the line before the number.

1. Why do things thrown upward fall down?

A. Gravity ran out

B. friction causes them to fall

C. gravity make things fall

D. the kinetic energy of things are used up.

2. What class of lever is a crowbar?

A. First

B. second

C.third

D.fourth

3. Why are there no machines with an efficiency of 100%?

A. Machines are not durable

B. machines tend to deteriorate over time

C. machines are not capable of handling heavy jobs

D. machines are affected by external forces such as friction

4. How is mass related to gravity?

A. If you double the mass of an object, its gravitational force is tripled.

B. If you double the mass of an object, its gravitational force is halved.

C. If you double the mass of an object, its gravitational force is doubled.

D. If you double the mass of an object, its gravitational force is increased by 1.5 times.

5. Which of the following is a safety precaution when using a machine

A. Running on ramps c. holding on the handrails of a ramp

B. Holding a knife upwards

C.holding on the handrails of a ramp

D. using sharp object without adult supervision

6. Which of the following converts energy from a waterfall into electrical energy?

A. Geothermal power plant

B. hydroelectric power plant

C. nuclear power plant

D. solar power plant

7. How will you describe a compound machine

A. A combination of two simple machine

B. A combination of more than three machines

C. c. two separate machines that operates separately

D. three separates machine that operates separately

8. How does a percussion instrument produce a sound?

A. By containing their vibrations

B. By passing the vibrations to the air

C. by absorbing vibrations from the air

D. none of the above

9. Which of the following materials convert electricity to light energy?

A. Fan

B. refrigerator

C. incandescent bulb

D. all of these

10. How is the mechanical advantage of the machine computed?

A. By dividing the input force by the output force

B. By dividing the output force by the input force

C. By multiplying the input force by the output force

D. By multiplying the output force by the input force

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