Topic 1- Forces And Motion

Question 1

What does the gradient of a distance-time graph represent?

Answer 1

Speed

Question 2

What does a flat line represent on a distance-time graph?

Answer 2

The object is stationary

Question 3

What does a steep line represent on a distance-time graph?

Answer 3

A fast speed

Question 4

What does it mean if a distance-time graph has a curved line?

Answer 4

The object is acceleration or decelerating.
If the curve is steepening= speeding up
If the curve is levelling= slowing down.

Question 5

Equation for speed

Answer 5

Speed= distance divided by time

Question 6

Describe an experiment to investigate the motion of everyday objects

Answer 6

1) lay 4X1 metre rules along a surface.
2) push the car and time how long it takes to travel 50cm
3) plot the data on a distance-time graph
4) repeat experiments with different strengths of force.

Question 7

Equation for acceleration

Answer 7

(Change in velocity) divided by time

Question 8

What does the gradient of a velocity-time graph represent?

Answer 8

Gradient= acceleration

Question 9

What does a flat line on a velocity-time graph represent?

Answer 9

A constant speed

Question 10

What does a steep gradient of a velocity-time graph represent?

Answer 10

A high acceleration/ deceleration

Question 11

What does the area under a velocity-time graph represent?

Answer 11

Distance travelled

Question 12

What does a curved gradient of a velocity-time graph represent?

Answer 12

Change in acceleration

Question 13

What is a force?

Answer 13

A force is something that acts on a body. It can make the object change shape, speed and direction.

Question 14

What are examples of forces?

Answer 14

Weight, friction, thrust, magnetic etc.

Question 15

What is a vector quantity

Answer 15

Something that has a magnitude and direction

Question 16

What is a scalar quantity

Answer 16

Something that only has a magnitude. No direction.

Question 17

What quantity is a force

Answer 17

A vector quantity

Question 18

What do unbalanced forces cause and what do balanced forces cause

Answer 18

Unbalanced forces cause an object to accelerate.

Balanced forces will either produce a steady speed or no movement.

Question 19

What is friction

Answer 19

A force that opposes movement

Question 20

What is the equation for force

Answer 20

Force= mass X acceleration

Question 21

Equation for weight

Answer 21

Weight= mass X g

Question 22

What forces act on a falling object (terminal velocity set out q)

Answer 22

1) At first, the only force acting on the object is its weight so there is a large acceleration downwards. (A big resultant force)
2) As speed increases , so does air resistance.
3) this decreases the resultant force so the object doesn’t accelerates as greatly.
4) eventually drag= speed
5) no unbalanced force= terminal velocity

Question 23

Describe an experiment to investigate falling objects

Answer 23

1) Collect a bunch of sycamore seeds of similar mass but different wing lengths.
2) drop each seed from the same height (higher the better) and time how long it takes to reach the floor.
3) repeat 3 times for each length and find average.
4) plot graph of time over length of wings.
* the bigger the surface area, the bigger the drag. This means that it will have a lower terminal velocity and so it falls more slowly.

Question 24

What factors affect stopping distance?

Answer 24

Speed
Mass of car
Reaction time
Road conditions

Question 25

Equation for momentum

Answer 25

Momentum= mass X velocity

Question 26

How do car safety features such as seat belts and crumple zones reduce injuries?

Answer 26

They increase the stopping time so that there is a smaller overall force acting on the person.

Question 27

What is the law of conservation of momentum?

Answer 27

Momentum before= momentum after. | Only if the object has not been acted on by external forces.

Question 28

Equation for force in terms of momentum?

Answer 28

Change in momentum / time.

Question 29

What is newtons 3rd law?

Answer 29

F= m X a. | To every action, there is an equal and opposite reaction.

Question 30

Equation for moments

Answer 30

Moment= force X perpendicular distance from pivot

Question 31

Where does the weight of the body of an object act through?

Answer 31

It's centre of gravity.

Question 32

What happens if you add more weights to a plank of wood.

Answer 32

The pivots pushing up have to exert a larger force in order to balance the new mass

Question 33

Describe an experiment to see if an object obeys hooke's law

Answer 33

1) Set up a clamp and stand with a spring and hanging mass. (Have extra weights) 2) measure the length of the spring with no load. 3) add one mass at a time and after it has come to a rest, measure the extension. 4) repeat this for all the loads. 5) once done, repeat and find average. * plot these results on force-extension graph. If the line is a straight line, then the object obeys hooke's law.

Question 34

What is hooke's law?

Answer 34

The extension of a stretched wire is proportional to its load.

Question 35

What does it mean if a material is elastic?

Answer 35

It has the ability to recover its original shape after the forces causing its deformation have been removed.

Question 36

What does it mean if a force-extension graph has a curved line

Answer 36

The object is plastic and has passed its point of elasticity. This means that it is permanently stretched past its original length.

Question 37

Why is gravitational field strength different on other planets?

Answer 37

This is because different planets have offering masses.

Question 38

What does gravitational cause things to do?

Answer 38

Moons orbit planets Planets orbit the sun Comets orbit the sun Artificial satellites orbit the Earth.

Question 39

What are they comets of comets, moons and planets like?

Answer 39

Comets are highly elliptical | Moons and planets are slightly elliptical but assumed to be circular

Question 40

Equation for orbital speed?

Answer 40

(2 X pi X orbital radius)/ time

Question 41

What is a universe?

Answer 41

A large collection of galaxies

Question 42

What are galaxies?

Answer 42

A large collection of billions of stars

Question 43

Where is our solar system?

Answer 43

In the Milky Way