Grade 12 Physics Homework Practice: Energy

Energy Homework Practice

Grade 12 Physics Energy Homework Practice Easy 20 Questions 7 Views

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Grade 12 Physics Homework Practice: Energy

Energy Homework Practice

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Grade: Grade 12

Subject: Physics

Topic: Energy

Time: 20 Minutes

Difficulty: Easy

Questions: 20

Instructions:
Read each question carefully and answer in full sentences or show your work where needed. Use the appropriate physics formulas and units. Questions are arranged from easier to more challenging.

Skills Practiced:

Energy
Physics
Critical Thinking
Problem Solving

1Question

What is energy in physics?

2Question

What is the SI unit of energy?

3Question

Name one form of energy stored in an object due to its position.

4Question

A book is sitting on a table. Is it mainly moving energy or stored energy?

5Question

Write the formula for kinetic energy.

6Question

What happens to kinetic energy if the speed of an object doubles?

7Question

A 2 kg object is moving at 3 m/s. Calculate its kinetic energy.

8Question

Write the formula for gravitational potential energy near Earth’s surface.

9Question

A 5 kg object is lifted 4 m above the ground. Use g = 9.8 m/s^2. Calculate its gravitational potential energy.

10Question

If an object is lifted higher, what happens to its gravitational potential energy?

11Question

What type of energy does a stretched rubber band store?

12Question

State the law of conservation of energy.

13Question

A roller coaster moves from the top of a hill to the bottom. What energy change mostly occurs?

14Question

A machine does 200 J of work in 10 s. What is its power?

15Question

What is the relationship between power and energy?

16Question

A 10 W light bulb uses 10 J of energy each second. How much energy does it use in 5 s?

17Question

A student lifts a 3 kg backpack to a shelf 2 m high. Use g = 9.8 m/s^2. Calculate the increase in gravitational potential energy.

18Question

A 4 kg cart has a speed of 6 m/s. Calculate its kinetic energy.

19Question

A 2 kg ball is dropped from rest from a height of 10 m. Ignoring air resistance, what energy form increases as it falls?

20Question

A 1,000 W heater runs for 15 minutes. How much energy does it use in joules?

Answer Key

#	Answer
1	Energy is the ability to do work or cause change.
2	The SI unit of energy is the joule (J).
3	Gravitational potential energy.
4	It is mainly stored energy, or potential energy.
5	Kinetic energy = 1/2 mv^2.
6	Its kinetic energy becomes four times larger.
7	KE = 1/2(2)(3^2) = 9 J.
8	GPE = mgh.
9	GPE = mgh = 5 × 9.8 × 4 = 196 J.
10	Its gravitational potential energy increases.
11	Elastic potential energy.
12	Energy cannot be created or destroyed; it can only be transformed from one form to another.
13	Gravitational potential energy changes into kinetic energy.
14	Power = work/time = 200/10 = 20 W.
15	Power is the rate at which energy is transferred or used.
16	Energy = power × time = 10 × 5 = 50 J.
17	GPE = mgh = 3 × 9.8 × 2 = 58.8 J.
18	KE = 1/2(4)(6^2) = 72 J.
19	Its kinetic energy increases as its gravitational potential energy decreases.
20	Energy = power × time = 1000 × 900 = 900,000 J.