Work and energy

Question 1

What is the formula for calculating work done?

Answer 1

Work done = Force x Distance x cos(θ)

Question 2

True or False: Work is a scalar quantity.

Answer 2

True

Question 3

What unit is work measured in?

Answer 3

Joules (J)

Question 4

If a force of 10 N moves an object 5 m in the direction of the force, how much work is done?

Answer 4

50 Joules

Question 5

Fill in the blank: The work-energy principle states that the work done on an object is equal to the change in its ______.

Answer 5

kinetic energy

Question 6

What is the formula for kinetic energy?

Answer 6

Kinetic Energy = 0.5 x mass x velocity²

Question 7

What is the unit for energy?

Answer 7

Joules (J)

Question 8

True or False: Potential energy is energy stored due to an object’s position.

Answer 8

True

Question 9

What is the formula for gravitational potential energy?

Answer 9

Potential Energy = mass x gravitational field strength x height

Question 10

What does ‘g’ represent in the gravitational potential energy formula?

Answer 10

Gravitational field strength, approximately 9.81 N/kg on Earth

Question 11

What is the principle of conservation of energy?

Answer 11

Energy cannot be created or destroyed, only transformed from one form to another.

Question 12

Fill in the blank: The unit of power is the ______.

Answer 12

Watt (W)

Question 13

How is power related to work and time?

Answer 13

Power = Work done / Time taken

Question 14

If 100 Joules of work is done in 5 seconds, what is the power output?

Answer 14

20 Watts

Question 15

True or False: Machines can create energy.

Answer 15

False

Question 16

What is mechanical energy?

Answer 16

The sum of kinetic and potential energy in a system.

Question 17

What is the formula for elastic potential energy?

Answer 17

Elastic Potential Energy = 0.5 x spring constant x extension²

Question 18

In the context of work and energy, what does ‘θ’ represent?

Answer 18

The angle between the force and the direction of motion.

Question 19

True or False: Work can be negative.

Answer 19

True

Question 20

What is the effect of friction on work done?

Answer 20

Friction opposes motion, reducing the work done on an object.

Question 21

Fill in the blank: The total mechanical energy of a system remains constant in the absence of ______.

Answer 21

non-conservative forces (like friction)

Question 22

What is an example of a non-conservative force?

Answer 22

Friction

Question 23

What happens to kinetic energy when an object comes to a stop?

Answer 23

It is transformed into other forms of energy, such as thermal energy.

Question 24

What is the relationship between work and energy in terms of units?

Answer 24

Both work and energy are measured in Joules.

Question 25

True or False: Power is the rate at which work is done.

Answer 25

True

Question 26

What is the significance of a positive work value?

Answer 26

It indicates that energy is being added to the system.