Forces and motion

Question 1

what does the gradient of a distance time graph represent?

how do we find the speed at a point on a curve

Answer 1

speed

draw a tangent

Question 2

what is velocity and acceleration

Answer 2

velocity is speed in a direction

acceleration is speeding up or slowing down

Question 3

what does:
a straight line in the middle of the graph
diagonal from left to right
straight line on the axis
line below the axis
diagonal from right to left

mean on a velocity time graph

Answer 3

a straight line in the middle of the graph- constant velocity

diagonal from left to right- deceleration

straight line on the axis- stationary

line below the axis- moving backwards

diagonal from right to left- acceleration

Question 4

what does the gradient on a velocity time graph indicate

what does the area under the gap indicate

Answer 4

acceleration

distance

Question 5

what is the relationship between force and acceleration

Answer 5

directly proportional, the bigger the resultant force the bigger the acceleration

Question 6

what’s the relationship between mass and acceleration

Answer 6

the bigger the mass the smaller the acceleration

Question 7

what is terminal velocity? how are the forces affected

Answer 7

the maximum velocity an object can move at. at terminal velocity the forces are balanced meaning they are moving at constant velocity

Question 8

what are 3 factors affecting air resistence. how do they affect it?

Answer 8

density of atmosphere- the gender the atmosphere the more air you need to push- higher air resistance

speed- the faster you are moving the more air you need to push- more air resistance

surface area- more surface area means there’s more air to push

Question 9

what 2 things is braking force dependant on

Answer 9

speed of vehicle

mass of vehicle

Question 10

what is the relationship between speed and braking force

Answer 10

the higher the speed the more braking force needed to stop the vehicle

Question 11

what are 3 things thinking distance is affected by

Answer 11

• tiredness/bad reaction time
• distractions
• being under the influence of drugs or alcohol

Question 12

what are 3 things braking distance is affected by

Answer 12

• condition of the vehicle (bad brakes and tyres)
• road conditions (icy wet roads)
• speed

Question 13

what happens when brakes of a vehicle are applied

Answer 13

friction between brakes and wheel reduces kinetic energy in vehicle and temperature of the brakes increases

Question 14

on a velocity time graph, which area is thinking distance and which is braking distance

Answer 14

thinking distance is the area under the graph when moving at constant velocity (straight line)

breaking distance is area under the graph at deceleration (diagonal from left to right)