Newton's laws

Question 1

what is newton’s first law?

Answer 1

the law of motion

Question 2

what did newton’s first law inscribe?

Answer 2

an object remains in the same state of motion unless a resultant force acts on it

Question 3

what does it mean when the resultant force of an object is zero? (2)

Answer 3

• the stationary object stays stationary

- the moving object continues to move at the same velocity (at the same speed and in the same direction)

Question 4

what is uniform motion?

Answer 4

constant velocity

Question 5

what is terminal velocity?

Answer 5

maximum speed of an object

Question 6

what can you deduce of the resultant force if the resultant forces acting on an object are balanced?

Answer 6

the resultant force is zero

Question 7

what can you deduce of the resultant force if the resultant forces acting on an object are not balanced?

Answer 7

the resultant force is NOT zero

Question 8

what happens when non-uniform motion occurs? and what does it affect?

Answer 8

-speed or direction changes, which affects velocity

Question 9

will opposite forces affect each other? (different axis)

Answer 9

• no
• horizontal forces will not affect the vertical movement and the vertical forces will not affect the horizontal movement.

Question 10

• describe the correlation between the vertical/ horizontal forces ?
• what effect does this have on the resultant force?
• what assumption can you make about acceleration?

Answer 10

• if the vertical/ horizontal forces are equal in size and opposite in direction, they are balanced,
• the vertical/ horizontal resultant force is zero.
• this means that there is no vertical/ horizontal acceleration.

Question 11

what is newton’s second law (equation)?

Answer 11

F = ma
Force(N) = mass(kg) x acceleration(m/s^2)

Question 12

The (F=ma) equation shows that the ACCELERATION of an object is:

Answer 12

• proportional to the resultant force on the object

- inversely proportional to the mass of the object

Question 13

what is the correlation between acceleration and force & mass?

Answer 13

• acceleration increases if the resultant force on it increases
• acceleration decreases if the mass of the object increases.

Question 14

what is the ratio of force over acceleration called?

Answer 14

-inertial mass.

Question 15

what is inertial mass?

Answer 15

-a measure of how difficult it is to change the velocity of an object.

Question 16

what is the motto for newton’s third law?

Answer 16

every action has an equal and opposite reaction

Question 17

what happens when two objects interact according to newton’s third law?

Answer 17

whenever two objects interact, they exert equal and opposite forces on each other

Question 18

it is important to remember that the two forces:

Answer 18

act on two different objects

are of the same type (e.g contact forces)

Question 19

3 examples of contact forces:

• a cat sat on the ground
• pushing a pram
• car tyre on a road

Answer 19

A cat sits on the ground

• the cat pulls the Earth up
• the Earth pulls the cat down

Pushing a pram

• the person pushes the pram forwards
• the pram pushes the person backwards

Car tyre on a road

• the tyre pushes the road backwards
• the road pushes the tyre forwards

Question 20

example of a non contact force:

Answer 20

A satellite in the Earth’s orbit

• the Earth pulls the satellite
• the satellite pulls Earth

Question 21

what does newton’s third law state?

Answer 21

-if body A exerts a force on body B, then body B will exert an equal opposite force on body A

Question 22

what is the weight of an object (directly) proportional to?

what assumption can you make about this regarding a given gravitational field strength?

Answer 22

• weight of an object is directly proportional to its mass

- the greater the mass of the object - the greater its weight is.

Question 23

weight equation: (include units)

Answer 23

weight (N) = mass(kg) × gravitational field strength (N/kg)

w=mg

Question 24

how do we make a measurement of weight?
how can we do this?
what predictions can you make with evidence correlating to one of newton’s laws?

Answer 24

• we have to measure the force pulling the object towards the centre of the Earth.
• we do this by balancing it with a known force.
• if the object is stationary, Newton’s third law then tells us that the known force is the same as the weight.

Question 25

how does a spring balance work?

what does the distance stretched correlate to?

Answer 25

• it will stretch until the force from the spring is enough to balance the weight of the object,
• the distance the spring in it has stretched indicates the force it is exerting to hold up the object.

Question 26

what did newton’s second law state?

Answer 26

if a non-zero resultant force acts on an object, it will cause it accelerate

Question 27

what is inertia?

Answer 27

the tendency for the motion of an object to be remain unchanged