Section 1 - Forces and Motion

Question 1

What is the equation for SPEED?

Answer 1

Speed = Distance Moved / Time Taken

Question 2

In a distance-time graph, how is the speed represented?

Answer 2

The gradient is equal to the speed

Question 3

In a distance-time graph, what does a curve mean?

Answer 3

Curves represent acceleration or deceleration

Question 4

What is the equation for ACCELERATION?

Answer 4

Acceleration = Change in Velocity / Time Taken

Question 5

In a velocity-time graph, how is the acceleration represented?

Answer 5

The gradient is equal to the acceleration

Question 6

In a velocity-time graph, how is the distance travelled in a certain period of time represented?

Answer 6

The area under any section of the graph is equal to the distance travelled in that time interval

Question 7

What is the equation for FORCE?

Answer 7

Force = Mass x Acceleration

Question 8

What is the equation for WEIGHT?

Answer 8

Weight = Mass x Gravitational Field

Question 9

What are the five main types of forces?

Answer 9

1. Gravity or Weight (straight downwards)
2. Reaction Force (straight upwards)
3. Electrostatic Force (between two charged objects)
4. Thrust (speed something up)
5. Drag or Air Resistance (slowing things down)

Question 10

Where does the weight of a body act through?

Answer 10

Its centre of gravity

Question 11

What is friction?

Answer 11

Friction is a force that opposes motion

Question 12

Describe an experiment to investigate the motion of a toy car

Answer 12

Set up two light gates. Measure the distance of the two light gates. Allow the car to travel between the two light gates and work out its speed

Question 13

What are the two forces acting on falling objects?

Answer 13

Drag and Weight

Question 14

Why do falling objects reach a terminal velocity?

Answer 14

When objects first set off, they have much more force accelerating them than resistance slowing them down. As the velocity increases, the resistance builds up.

This gradually reduces the acceleration until eventually the resistance force is equal to the accelerating force and then it won’t be able to accelerate any more

Question 15

Describe an experiment using sycamore seeds to investigate the forces acting on a falling object

Answer 15

Time the time taken for a sycamore seed to hit the ground from an assigned height.

You will find out that the longer the wings are, the longer the time taken for it to hit the ground

Question 16

What is Newton’s Third Law? *

Answer 16

If object A exerts a force on object B, then object B exerts the exact opposite force on object A

Question 17

What is a vector quantity? *

Answer 17

A vector has size and direction

Question 18

What is a scalar quantity? *

Answer 18

A scalar only has size

Question 19

Is force a vector quantity or a scalar quantity? *

Answer 19

it is a vector quantity

Question 20

How do you find the resultant face of forces that act along a line? *

Answer 20

By adding them end to end

Question 21

What factors affect vehicle stopping distance?

Answer 21

1. Speed - the faster you go, the further it takes to stop
2. Mass - the larger the mass, the longer it takes to stop
3. Road Condition - the better the conditions, the better
4. Reaction Time - the faster, the better

Question 22

What is the equation for MOMENTUM? *

Answer 22

Momentum = Mass x Velocity

Question 23

What is the conservation of momentum? *

Answer 23

Momentum is conserved when no external forces act. The total moment after is the same as it was before.
p (1) = p (2)
m (1) x v (1) = m (2) x v (2)

Question 24

What is the equation for FORCE ACTING? *

Answer 24

Force Acting (N) = Change in Momentum (kg m/s) / Time Taken For Change to Happen (s)

Question 25

Why do cars have crumple zones, seat belts and air bags? *

Answer 25

Crumple Zones - crumple on impact, increasing the time taken for the car to stop Seat Belts - stretch slightly, increasing the time taken for the wearer to stop. This reduces the forces acting on the chest. Air Bags - increase the time taken for the individual to stop.

Question 26

What is the equation for MOMENT?

Answer 26

Moment (Nm) = Force (N) x Perpendicular Distance (m)

Question 27

What is the principle of moments? *

Answer 27

If an object is balanced, then total anticlockwise moments is equal to total clockwise moments

Question 28

If a beam supported by springs has a 10 N weight added in the centre of it, what would the upward force of each spring have to be? *

Answer 28

5 N

Question 29

Describe an experiment to investigate the relationship between extension and force

Answer 29

Attach a spring to a newton meter and measure its length Add a 50g weight and measure again Continue to add another weight and take measurements Do this up to 400g By plotting a graph from the results, you can see the extension increases with force; as each time a weight is added, the spring gets longer.

Question 30

Describe what is happening on a force-extension graph

Answer 30

It starts off linear as it is obeying Hooke's Law There is a point where it starts to curve, this is its elastic limit and from then on, the material will be permanently stretched

Question 31

What is elastic behaviour?

Answer 31

If the material can return to its original shape once the forces are removed

Question 32

What is gravitational field strength?

Answer 32

Gravitational field strength is how strongly something pulls an object towards it.

Question 33

Which has a greater gravitational field strength: the Earth or the Moon? How do we know this?

Answer 33

The Earth has a greater gravitational field strength The pull of the Earth means that we can only jump for a few seconds, but we can jump for a long time on the moon.

Question 34

What does gravitational force cause?

Answer 34

- Causes moons to orbit planets - Causes the planets to orbit the sun - Causes artificial satellites to orbit the Earth - Causes comets to orbit the sun

Question 35

What are the differences in the orbits of comets, moons and planets?

Answer 35

Orbits of moons and planets are slightly elliptical Comets have a very elliptical orbit. They travel fast when they are near to the sun and slower when they are further away.

Question 36

What is the equation for ORBITAL SPEED?

Answer 36

Orbital Speed = (2 x pi x orbital radius) / time period

Question 37

What is a universe?

Answer 37

A universe is a large collection of billions of galaxies

Question 38

What is a galaxy?

Answer 38

A galaxy is a large collection of billions of stars

Question 39

What is our solar system called?

Answer 39

The Milky Way galaxy