Physics term 2

Question 1

What is the unit of mass?

Answer 1

KG

Question 2

What is the unit of force

Answer 2

N

Question 3

Whats the unit of power

Answer 3

Watts

Question 4

Which of the following statements regarding momentum is true?

a) Momentum is a scalar quantity
b) Momentum is conserved in elastic collisions only
c) Momentum is the product of mass and velocity.
d) Momentum depends on the reference frame

Answer 4

D) Momentum is the product of mass and velocity

Question 5

An object weighs 19N on a planet where the acceleration is 3.8m/s squared what is the mass of the object

Answer 5

5.0kg

Question 6

Give one advantage and one disadvantage of wind turbines

Answer 6

1. No harmful gas released
2. Very noisy

Question 7

The diagram shows a rectangular metal block with dimensions 2.5cm3,04.5* the block is resting on the ground
The block exerts a pressure of 0.23 N/cm squared on the ground the angles that exerts pressure down is 4.5 and 2.5 what is the weight of the block

Answer 7

2.6N

Question 8

What happens to molecules of a gas when heated

Answer 8

They move faster and further apart

Question 9

What does Boyle law state

Answer 9

Pressure and volume of a gas have an inverse relationship

Question 10

Define the kinetic theory of matter.

Answer 10

Matter is made up of small particles in constant motion.

Question 11

State the relationship between pressure and volume at constant temperature.

Answer 11

Pressure is inversely proportional to volume.

Question 12

What is the SI unit of pressure?

Answer 12

Pascal (Pa).

Question 13

What happens to gas pressure when the temperature of a fixed volume of gas increases?

Answer 13

Pressure increases.

Question 14

Which process involves energy being released? A) Boiling B) Melting C) Freezing D) Evaporation

Answer 14

C

Question 15

What happens to particle motion when a substance is heated?

Answer 15

Particle motion becomes faster.

Question 16

What happens to gas molecules when cooled?

Answer 16

They move slower and get closer together.

Question 17

The volume of metal is 30 cm³, and its mass is 192g. Calculate the density of the metal. Include the unit

Answer 17

Density=mass/ volume
= 192/30= 6.4g/cm³

Question 18

Fig 2.1 shows a hammer hitting a nail. The mass of the hammer head is 0.15kg, and it’s speed is 8.0 m/s before contact. Calculate the change in momentum of the hammer head.
State the impulse given to the nail in the hammer and nail system.
The hammer head is in contact with the nail for 0.0015 s. Calculate the average force between the hammer and nail.
mass of hammer head is 0.15

Answer 18

1. Change in momentum= mass×velocity
   = 0.15×8.0= 1.2kg.m/s
2. Impulse= change in momentum= 1.3 N.s
3. Force = impulse/time = 1.2/0.0015= 800N

Question 19

A cyclist exerts a force 36N to move the bike forward. Calculate the work done by this force when the cyclist travels 250 m.

Answer 19

Work done= force×distance
W= 36×250= 9000J

Question 20

Describe how hydroelectric power station generates electrical power.

Answer 20

A hydroelectric power station generates electrical power by using the energy of flowing or falling water to turn a turbine connected to a generator.

Question 21

Calculate the efficiency of the TV given that the energy input is 100 J and the useful output is 30 J.

Answer 21

Efficiency=( useful output energy/input energy) * 100
30/100100
0.3100= 30

Question 22

What is the formula for calculating efficiency in an energy system?

Answer 22

Efficiency = Output/Input × 100

Question 23

What is the unit of work done in physics?

Answer 23

Joules

Question 24

A car of mass 1000 kg is moving at a velocity of 20 m/s. Calculate its momentum.

Answer 24

Momentum = Mass × Velocity = 1000 kg × 20 m/s = 20,000 kg·m/s

Question 25

What is the equation for calculating work done?

Answer 25

Work= force × distance

Question 26

If a device has an efficiency of 25% and an energy input of 200 J, what is the useful energy output?

Answer 26

Useful energy output=0.25×200=50J

Question 27

Describe how a student can measure the volume of a piece of metal using a measuring cylinder, displacement (Eureka) can, and water as shown in Fig. 2.1.

Answer 27

Fill the Eureka can with water until it overflows. Place a measuring cylinder beneath the spout to catch the displaced water. Submerge the metal piece in the Eureka can. Measure the volume of water collected in the cylinder, which equals the volume of the metal.

Question 28

Which apparatus do you need to determine density

Answer 28

Balance, measuring cylinder or Eureka can, ruler or caliper

Question 29

Which apparatus do you need to measure volume.

Answer 29

For regular objects a ruler For irregular objects, use a measuring cylinder or Eureka can to measure the volume by displacement of water.

Question 30

An object travels 50 meters in 10 seconds. What is its speed?

Answer 30

5 m/s

Question 31

A car accelerates from 10 m/s to 30 m/s in 5 seconds. Calculate the acceleration.

Answer 31

4 m/s²

Question 32

If a force of 15 N is applied to an object with a mass of 3 kg, what is the acceleration?

Answer 32

5 m/s²

Question 33

A ball falls with a weight of 50 N. If the gravitational field strength is 10 N/kg, what is the mass of the ball?

Answer 33

5 kg

Question 34

An object has a mass of 10 kg and a velocity of 2 m/s. What is its momentum?

Answer 34

20 kg·m/s

Question 35

A car with a mass of 1000 kg is moving at 20 m/s. Calculate its momentum.

Answer 35

20,000 kg·m/s

Question 36

Calculate the impulse when a force of 25 N acts for 4 seconds.

Answer 36

100 Ns

Question 37

An object weighing 100 N is lifted to a height of 2 meters. Calculate the work done.

Answer 37

200 J

Question 38

A machine transfers 500 J of useful energy out of 800 J of total energy. What is its efficiency?

Answer 38

62.5

Question 39

If an object has a kinetic energy of 100 J and a mass of 2 kg, calculate its velocity.

Answer 39

10 m/s

Question 40

An object of mass 5 kg is at a height of 10 meters. Calculate its potential energy (g = 10 m/s²).

Answer 40

500 J

Question 41

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

Answer 41

9 J

Question 42

Work done to move a box is 300 J. If the force applied is 50 N, calculate the distance moved.

Answer 42

6 m

Question 43

A machine does 1000 J of work in 5 seconds. Calculate its power.

Answer 43

200 W

Question 44

A vehicle with a mass of 1500 kg stops from 20 m/s in 5 seconds. Calculate the average force applied.

Answer 44

6000 N

Question 45

If the efficiency of a machine is 40% and the energy input is 1000 J, calculate the useful energy output.

Answer 45

400 J

Question 46

A 5 kg object accelerates at 3 m/s². Calculate the force acting on it.

Answer 46

15 N

Question 47

A 10 kg object is acted upon by a force of 50 N. Calculate its acceleration.

Answer 47

5 m/s²

Question 48

A car with a mass of 800 kg moving at 15 m/s is brought to rest. What is the change in momentum?

Answer 48

12,000 kg·m/s

Question 49

Calculate the velocity of an object with a momentum of 200 kg·m/s and a mass of 4 kg.

Answer 49

50 m/s

Question 50

A force of 20 N acts on a 2 kg object for 5 seconds. Calculate the impulse.

Answer 50

100 Ns

Question 51

A man pushes a trolley with a force of 120 N over a distance of 3 meters. Calculate the work done.

Answer 51

360 J

Question 52

A box is moved 4 m with a force of 25 N. Calculate the work done.

Answer 52

100 J

Question 53

Calculate the power if 500 J of work is done in 10 seconds.

Answer 53

50 W

Question 54

An object of mass 3 kg moving at 4 m/s hits a wall and stops. Calculate the impulse.

Answer 54

-12 Ns