Forces And Motion

Question 1

What is newtons seconds law

Answer 1

The bigger the five acting in an object , the faster the object will speed up . Objects with greater mass require bigger forces than those with smaller mass to make them accelerate at the same speed

Question 2

What equation links force , mass and acceleration

Answer 2

Force =massn x acceleration

Question 3

What is displacement

Answer 3

Distance travelled from your starting point e.g if you walked from home and back again your displacement would be 0metres

Question 4

What is instantaneous speed

Answer 4

Speed at a point measured over a small time interval

Question 5

Why did the trolley go faster down the ramp

Answer 5

Because the size of acceleration increased due to decrease in frictional force

Question 6

How do you calculate acceleration

Answer 6

Time

Question 7

How do you calculate distance

Answer 7

Area under the line is distance travelled

Question 8

How do you calculate average speed

Answer 8

Time taken

Question 9

How do you calculate density

Answer 9

Volume

Question 10

Do objects always have the same mass and Weight

Answer 10

Yes they always have the same mass , if an object is in a gravitational field it will also have weight which is measured in newtons .

Question 11

What do balanced forces do to an objects speed

Answer 11

They make the speed reach terminal velocity

Question 12

How does gravity affect falling objects

Answer 12

It causes them to accelerate and as the speed of a falling object increased so do the frictional forces until they balance the gravitational force

Question 13

What is Newton’s first law of motion

Answer 13

Things don’t speed up slow down or change direction unless you push or pull them . A body would continue to move in a straight line at a steady speed unless a resultant force was acting on the body . If forces are balanced the object will continue the same movement

Question 14

How do you calculate weight

Answer 14

Mass x gravitational field strength

Question 15

What is earths gravitational field strength

Answer 15

10

Question 16

How do you reduce mass

Answer 16

You reduce the amount of particles in the object

Question 17

What is velocity

Answer 17

Speed in a given direction

Question 18

What is the resultant forces

Answer 18

You subtract the forces which point along the sane direction so you subtract the driving force from the resistive force e.g driving force = 4500 n resistive force =4450 n so resultant force = 50

Question 19

How do you calculate acceleration for force

Answer 19

A=f once divided by mass

Question 20

What happens when a skydiver jumps out of a plain

Answer 20

His weight is greater than his air resistance so he accelerates downwards.this causes his air resistance to increase until it balances his weight. At this Point his velocity is constant. When his parachute opens, his air resistance is greater than his weight, so he decelerates . This causes his air resistance to decrease until it balances his weight

Question 21

What is a force

Answer 21

A push or a pull

Question 22

What is magnetic force

Answer 22

Attracts magnets or repels magnets

Question 23

What is Weight

Answer 23

Keeps the object still and not floating

Question 24

Upthrust

Answer 24

Keeps objects floating in water

Question 25

Friction

Answer 25

Resistive force

Question 26

Electrostatic

Answer 26

Repulsion of like charges and attraction of unlike charges

Question 27

Air resistance

Answer 27

Resistive force

Question 28

Lift

Answer 28

Upwards force on an aeroplane

Question 29

Thrust

Answer 29

Forwards force

Question 30

Drag

Answer 30

Frictional force caused by particles colliding with a body p

Question 31

Tension

Answer 31

Force on something being stretched

Question 32

Compression

Answer 32

Force on something being squashed

Question 33

Contact forces

Answer 33

Friction drag

Question 34

Bon contact forces

Answer 34

Weight electrostatic

Question 35

What is ticker timer

Answer 35

The ticker timer makes dots on a paper tape every fiftieth of a second. So if a piece of tape is pulled through the timer for a second there will be 50 dots on it.

Since the spaces between the dots take such a short time (1/50 s) the ticker timer is a very useful instrument for measuring short intervals of time.

A piece of tape is shown in the diagram. You can see that the faster the tape is pulled through the timer the furthest apart the dots get. If the tape is pulled through at a steady speed the dots remain the same distance apart.

We have to be very careful here; as there is 1/50 s between dots we must count the number of SPACES and not the number of dots themselves.

To work out the velocity of the tape all we need to do is to measure the length of tape that goes through in the time given by the number of spaces.

If you have a length of tape with 50 spaces then it took 50/50 s or 1s to go through the timer. So if there are 5 spaces it took 1/10th of a second

Question 36

How do you calculate speed on ticker tape

Answer 36

Example problems
Working out the speed

The piece of tape in the diagram is 5 SPACES long.
Each space is 1/50 s so five spaces will be 5/50 s or 1/10s.
So the piece of tape went through the timer in 1/10s. The piece of tape is 7 cm long.
If 7cm of tape go through in 1/10 s then 70cm will go through in 1 s.
The speed is then 70 cm/s.

Question 37

What forces are on falling objects

Answer 37

Drag and weight , the drag increases as speed increases until drag = weight so there is no acceleration , constant terminal velocity