P4

Question 1

What is a force?

Answer 1

It is a push or pull on an object that is caused by it interacting with another object

Question 2

What are contact forces?

Answer 2

• This is when objects are touching when the forces is acting
• For example-Friction is a contact force between two objects that slide past each other which prevents motion

Question 3

What are non-contact forces?

Answer 3

Forces between objects that are not touching each other

Question 4

What is newtons third law?

Answer 4

• When two objects interact, the foces they exert on each other are equal and opposite

Question 5

What is mass?

Answer 5

The amount of matter in an object-Kg

Question 6

What is gravity?

Answer 6

The force of attraction between masses

Question 7

What is weight?

Answer 7

• A downward force
• weight(N)= Mass(Kg) x gravitational field strength(N/Kg)

Question 8

What are scalars?

Answer 8

• Numbers that tell you the size of something youre measuring
• for example mass

Question 9

What are vectors?

Answer 9

• tells you the size of something and the direction of it
• for example force-as it has a size and can be applied in a specific direction

Question 10

How is the motion of an object described?

Answer 10

By its:
* speed
* direction of travel
* whether its speed is changing

Question 11

How do you calculate speed?

Answer 11

Average speed(m/s) = distance(m) / time(s)

Question 12

What is acceleration?

Answer 12

• The change in velocity of an object over a certain amount of time
• Speeding up-acceleration
• slowing down-deceleration

Question 13

What is the equation for acceleration and constant acceleration?

Answer 13

• Acceleration(m/s(power of 2))=Change in speed(m/s)/Time taken(s)
• Final speed(power of 2)-initialspeed(PO2) = 2xAcceleration(m/s(PO2))xDistance(m)

Question 14

What do distance time graphs tell you?

Answer 14

• Different parts describe motion of the object
• Gradient-average speed
• Steeper means faster
• Flat section means stopped
• straigh uphill means steady speed
• Curves represent acceleration
• steepening means speeding up
• leveling off means slowing down

use the gradient exaquation to work out average speed= change in y /// change in x

Question 15

What do velecoity time graphs tell you?

Answer 15

• Used to tell you average accelration
• Flat- steady velocity
• steeper the graph means the more the avareage acceleration or deceleration
• /-acceleration
• -deceleration
• straight line-constant acceleration
• Area under any section of graph is equal to the distance travelled in that time interval

use the gradient exaquation to work out average acceleration= change in y /// change in x

Question 16

What is a resultant force?

Answer 16

• It is the overall force on a point or object
• found by adding forces on the same direction then taking it away from the forces on the other direction

Question 17

What is newtons first law?

Answer 17

• If the resultant force on a moving object is zero, it will continue to move at a constant speed in a straight line
• If the resultant force on a stationary object is zero, the object will remain stationary

Question 18

What is momentum?

Answer 18

• The greater the mass of an onbject the greater its velocity, the more momentum it has
• momentum(kg m/s)=mass(Kg) x velocity(m/s)

Question 19

What is newtons second law?

Answer 19

• The change of momentum is proprtional to the size of the resultant force ans the time over which the force acts on the object
• Change momentum(kg m/s)=resultant force(N)xTime for which it acts(s)
• Force(N) = mass(kg) x acceleration(m/s(Power of 2))

Question 20

What is the law of conservation of momentum?

Answer 20

In a collision when no other external forces act, momentum is conserved-i.e. the total momentum after a collision is the same as it was before

Question 21

What is inertia?

Answer 21

The tendency for an objects movement to remain unchanged- i.e. stationary objects tend to remain stationary and moving objects tend to keep moving

Question 22

What is a moment?

Answer 22

• The rotational effect of a force
• Moment of a force(Nm) = force(N) x distance(m)

Question 23

What are levers?

Answer 23

• Transfers the rotational effect of a force
• increases the distance from the pivot that the force is applied-increasing the size of the moment created
• useful for lifting things and moving things easier

Question 24

What are gears?

Answer 24

• Circular disks with teeth around them
• The teeth of the gears interlock and cause other gears to move
• Due to this linkage, when one gear is spinning clockwise it will cause the next one to spin clockwise this alternates when you go from gear to gear
• force does not change within gears
• smaller gears turn quicker than larger gears

Question 25

What is stopping distance equation?

Answer 25

stopping distance= reaction distance + braking distance

Question 26

What is work done?

Answer 26

• It is when a force makes an object move and energe is transferred
• work done(Nm or J) = force(N) x distance(m)

Question 27

What is the equation for gpe and kinetic energy?

Answer 27

gpe(J) = mass x g field strength(N/kg) x height(m)
kinetic energy= 0.5 x mass(kg) x speed(m/s)(power of 2)

Question 28

What is power?

Answer 28

• The rate at which energy is transferred(or work is done) in a system
• power(W) = energy transferred (J) / time (s)

Question 29

What is inertial mass?

Answer 29

• A measure of how difficult it is to change the velocity of an object
• Force(N) = mass x (acceleration(m/s2)

Question 30

What is friction?

Answer 30

A force between two objects in contact trying to slide past one another.
Opposes the direction of motionn

Question 31

What is kinetic energy?

Answer 31

Energy an object possesses due to motion