Physics - Topic 2 - Forces and Motion

Question 1

Describe the difference between scalar and vector quantities

Answer 1

Scalar has magnitude only Vector has magnitude and direction

Question 2

What is a resultant force?

Answer 2

The overall force acting on an object

Question 3

What is the difference between mass and weight?

Answer 3

Mass has magnitude only (scalar) Weight has direction (vector) Mass is measured in kg Weight in measured in N

Question 4

What factors affect the weight of an object?

Answer 4

Mass, m (kg) Gravitational Field Strength, g (N/kg)

Question 5

Calculate the resultant force on the car

Answer 5

500N - 500N = 0N

Question 6

Calculate the resultant force on the car

Answer 6

500N - 200N = 300N forwards

Question 7

Calculate the resultant force on the car.

Answer 7

500N - 200N = 300N backwards

Question 8

Describe the motion of the car.

Answer 8

Moving at a constant velocity.

Question 9

Describe the motion of the car

Answer 9

Accelerates to the right.

Velocity increases in the forwards direction.

Question 10

Describe the motion of the car

Answer 10

Velocity decreases

Car decelerates

Question 11

Write an equation that links weight, mass and gravitational field strength

Answer 11

Weight = mass x gravitational field strength

W = m x g

Question 12

What is the value of gravitational field strength, g, on Earth?

Answer 12

10N/kg

Question 13

What is the weight of a 90kg astronaut on Earth?

Answer 13

W = m x g

= 90 x 10

= 900N

Question 14

A space probe has a mass of 3000N on Earth. What is its mass?

Answer 14

W = m x g

m = W ÷ g

= 3000 ÷ 10

= 300kg

Question 15

A mars rover with a mass of 185kg has a weight of 685N on Mars. Calculate the gravitational field strength on Mars.

Answer 15

W = m x g

g = W ÷ m

= 685 ÷ 185

= 3.70N/kg

Question 16

The mass of a spanner on Earth is 0.2kg, and its weight is 2N. The spanner is taken to the Moon as part of a toolkit.

Compare the mass and weight of the spanner on the Moon.

Answer 16

mass of the spanner is the same on the moon.

Weight will be less on the Moon.

as the gravitational field strength is smaller on the Moon.

Question 17

Describe what acceleration means.

Answer 17

Change in velocity in a certain time.

or

a = (v-u)÷t

Question 18

What two factors affect the size of acceleration of an object?

Answer 18

The size of the force (bigger force = bigger acceleration)

The size of the mass (bigger mass = smaller acceleration)

Question 19

What is the equation that links force, mass and acceleration?

Answer 19

force = mass x acceleration

F = m x a

Question 20

A motorcycle has a mass of 200kg. What force is needed to give it an acceleration of 7m/s²?

Answer 20

F = m x a

= 200 x 7

= 1400N

Question 21

A car with a mass of 1500kg is accelerated with a force of 800N. Calculate the acceleration of the car.

Answer 21

F = m x a

a = F ÷ m

= 800 ÷ 1500

= 0.53m/s²

Question 22

What is inertial mass?

Answer 22

The force on an accelerating object divided by its acceleration

Question 23

A force of 160N on a bike provides an acceleration of 2m/s². Calculate the intertial mass of the bike and its rider.

Answer 23

mass = F ÷ a

= 160 ÷ 2

= 80kg

Question 24

What conclusion can be made from this graph?

Answer 24

acceleration is proportional to force