Motion And Forces

Question 1

What is displacement

Answer 1

The distance from a to b measured in a straight line

Question 2

What is the difference between speed and velocity

Answer 2

Speed only has size (magnitude) whereas velocity tells you it’s speed and direction

Question 3

In a distance time graph, what do these show:
Horizontal line
Diagonal line (not steep)
Diagonal line (steep)

Answer 3

Not moving
Moving slowly
Moving fast
Steeper the gradient if the line, the faster the person is moving.
The gradient can be used to work out the speed

Question 4

What is a vector quantity

Answer 4

A measurement with size and direction such as displacement and velocity

Question 5

What is acceleration

Answer 5

The change in velocity and is calculated with:
Acceleration(m/s^2) = change in velocity(m/s) / Time(seconds)
a = (velocity 2 - velocity 1)/t
Velocity 2 is the velocity the object now has
Velocity 1 is the velocity the object had
t is the time taken for change in velocity

Question 6

What two things does 10m/s squared show

Answer 6

Every second the velocity increases by 10m/s and is increasing
If it were -10m/s squared, velocity would be decreasing

Question 7

In a velocity time graph what do the following mean:
Line on y = 0
Flat line not on y = 0 
Constant Diagonal line up
Constant Diagonal down

Answer 7

Stationary
Constant velocity
Positive acceleration
Negative acceleration

Question 8

How do you work out the distance traveled using a velocity time graph

Answer 8

Work out the area under the line in meters, this is the distance traveled

Question 9

What is a force

Answer 9

Something that is a push or a pull like gravity or upthrust

Question 10

What is a free body diagram

Answer 10

A diagram showing the forces on an object and its size.

Larger the arrow, the greater the force.

Question 11

What is an action reaction pair

Answer 11

When a force is applied to an object by another it is called the action force. This object then applies an equal amount of force back onto the other object and this is called the reaction force

Question 12

How can an action reaction pair be used to propel a rocket

Answer 12

Gas is pushed from the rocket in the action force. The reaction force from the gas pushes the rocket forwards

Question 13

What makes forces balanced

Answer 13

When two forces have the same force but are in opposite direction. E.g. On A plane with a constant height, the force from gravity is equal to the lift from the wings

Question 14

What makes unbalanced forces

Answer 14

When one force is greater than its opposite, they are unbalanced such as when a plane accelerates its thrust is greater than the drag (air resistance) so it accelerates

Question 15

What is resultant force

Answer 15

This is when more than one force acts on an object, the effect is the same as if they were one force, the resultant force. E.g. 100000N of thrust going right and 25000N on drag force to the left, the resultant force is 100000-25000N so it is 75000N right.

Question 16

A car accelerates by 3m/s squared and weighs 1500Kg, what is its force from the ending

Answer 16

F = m x a 
F = 1500 x 3
F = 4500N

Question 17

Why is a light bike important in races

Answer 17

The lighter the bike, the smaller its mass. This means less force is required to make it accelerate faster

Question 18

What is the difference between mass and weight

Answer 18

Mass is the quantity of matter in an object and doesn’t change where as weight is the force gravity applies to that object and can change depending on the strength of gravity.

Question 19

What is gravitational field strength

Answer 19

This is a way to describe the strength of gravity

Question 20

What is the gravitational field strength on earth

Answer 20

On earth the strength is 10N/Kg meaning every kilogram is pulled down by 10N