Topic 2- Forces

Question 1

What is force measured in?

Answer 1

Force is measured in newtons

Question 2

What is a force?

Answer 2

A force is a push or Pull

Question 3

What are forces measured with?

Answer 3

Forces Are measured with Newton metres.

Question 4

What is the gravitational force?

Answer 4

This is the attractive force exerted between bodies because of their masses. This force increases either or both of the masses is increased and decreased if they move further apart. Weight is a gravitational force of the earth.

Question 5

What is the normal reaction or contact force?

Answer 5

This is the Repusive force that stops to touching bodies moving into each other. The word normal means that this force acts at ninety degrees to the surface of the bodies. it is caused by repulsing molecule forces.

Question 6

What is the first step of a velocity of a skydiver?

Answer 6

The first step is when the sky driver steps of the plane this is only one force acting on it and that force is weight so the resultant force is weight. resultant force is large and downwards so acceleration is large and downwards as well. skydivers velocity increases downwards.

Question 7

What is the second step of the skydivers velocity?

Answer 7

Second step is when the skydivers velocity increases. This means the drag force increases upwards. So the resultant force decreases upwards. So the celebration decreases downwards. Skydiver continues to increase in velocity that at a smaller rate.

Question 8

What is the third step of the skydivers velocity?

Answer 8

Third step is when the skydivers velocity is so large that the drag equals weight. Result in force equals zero. Acceleration equals zero. The skydivers continue falling at the top constant velocity.

Question 9

What is the fourth step of the skydivers velocity?

Answer 9

The fourth step is when the skydiver pulls his parachute. The large drag force increases. The drag is larger than weight. So resultant force increases. So acceleration increases. So Velocity decreases downwards.

Question 10

What is the fifth and final step of the skydivers velocity?

Answer 10

This is when the velocity decreases. So drag decreases. Eventually the weight equals drag again. Resultant force equals zero, acceleration equals zero. Skydivers fall to the ground at second smaller terminal velocity.

Question 11

The gravitational field strength is smaller on the moon and the Earth suggest why.

Answer 11

Because the Earth has a bigger mass.

Question 12

The diagram shows a man pulling a child on a slide. The mass of a child and slate is 45 kg. The unbalanced force acting on the sledge is 49N.

State the equation linking unbalanced force, mass and acceleration.

Answer 12

F =MA

Question 13

The diagram shows a man pulling a child on a slide. The mass of a child and slate is 45 kg. The unbalanced force acting on the sledge is 49N.

Calculate the acceleration of the child and the sledge.

Acceleration= ……………… M/S^2

Answer 13

A = F/M
A = 49/45
=1.088 M/S^2

Question 14

The sledge is then placed at the top of the hill. When it slides down the hill, it accelerate at 1.3 M/S^2. The sledge accelerates from rest for 2.4 S.

State equation linking acceleration, velocity and time.

Answer 14

A= V-U/T

Question 15

The sledge is then placed at the top of the hill. When it slides down the hill, it accelerate at 1.3 M/S^2. The sledge accelerates from rest for 2.4 S.

Show that the sledge reaches a speed of approximately 3M/S after it has accelerated for 2.4 S.

Answer 15

V = 1.3 X 2.4

V= 3.1

Question 16

The driver of a car season obstacle in the road and stops the car as quickly as possible. The car stops without hitting the obstacle. State three factors that could have affected the stopping distance of the car.

Answer 16

1. Reaction time of the driver.
2. Friction of the tires.
3. Speed of the car.

Question 17

A rabbit runs across the road in front of a car. The driver appeals the brakes. State for factors that affect the chance of a rabbit escaping without being hit.

Answer 17

1. Vision of the rabbit if there is fog order on the windscreen.
2. the reaction time of the driver.
3. The speed of the rabbit.
4. The mass of the car.

Question 18

The diagram shows a man pulling a child on a slide. The mass of a child and slate is 45 kg. The unbalanced force acting on the sledge is 49N.

Suggest a reason why the man must pull the sledge with a force that is greater than 49N.

Answer 18

Because the friction between snow and the sledge. The ground is not level.

Question 19

Each airport has a run rate that is about 500 m long. When it lands the speed of the aeroplane is 40 M/S. Explain why the airline should not use an aeroplane that has more mass and needs a higher speed for landing.

Answer 19

Stopping distance affected by speed or mass. For heavier planes stopping distance is greater. Data shows most of the runway is already used.

Question 20

What’s stopping distance?

Answer 20

The distance the vehicle travels from the driver spotting a hazard and the car coming to a complete stop.

Question 21

What’s thinking distance?

Answer 21

The distance the vehicle travels from the driver spotting a hazard and the driver touching the breaks.

Question 22

What’s breaking distance?

Answer 22

The distance travelled from the driver touching the breaks to the car stops.

Question 23

What are the factors affecting driving (natural reaction)?

Answer 23

Tiredness,intoxicatloh: drugs or alcohol, age and distraction.

Question 24

What’s the difference between a vector in a scaler?

Answer 24

Vectors have a direction

Question 25

What are the similarities between doctors of scalars?

Answer 25

They both have a magnitude

Question 26

what’s the equation linking weight, mass and gravitational field strength?

Answer 26

W = m x g

Question 27

What is the equation linking force, mass and acceleration when acceleration is the subject?

Answer 27

A = f/m

Question 28

What is the definition of mass?

Answer 28

the amount of matter in an object