Forces and Motion - Forces, Movement, Shape and Momentum

Question 1

what are the effects of forces on a body?

Answer 1

• forces can act on a body to change the velocity, so the speed, direction or both.
• forces can change the shape of a body, stretching it squishing it or twisting it.

Question 2

what are the different types of forces?

Answer 2

• gravitational
• weight
• friction
• electrostatic
• air resistance (drag)
• tension (force in a spring)
• up thrust
• lift
• thrust

Question 3

what is a scalar quantity?

Answer 3

quantities with only magnitude (size)

Question 4

what is a vector quantity?

Answer 4

quantities with magnitude (size) and direction

Question 5

what type of quantity is force?

Answer 5

vector - magnitude measured in (N) and direction

Question 6

how would you calculate resultant force?

Answer 6

forces along a line can combine by addition

Question 7

what is friction?

Answer 7

a force that opposes motion, caused by surfaces rubbing

Question 8

what is the relationship between force, mass and acceleration?

Answer 8

Force = Mass x Acceleration

Question 9

what is the relationship between weight, mass and gravitational field strength?

Answer 9

Weight (N)= Mass (kg) x gravitational field strength (N/kg)

Question 10

what is the stopping distance made up of?

Answer 10

Stopping distance = Thinking distance + Breaking distance

Question 11

what is thinking distance affected by?

Answer 11

• tiredness
• alcohol/drugs
• speed of the car

Question 12

what is braking distance affected by?

Answer 12

• road conditions
• tyre conditions
• brake conditions
• speed of the car
• mass of the car

Question 13

how do forces reach terminal velocity?

Answer 13

• the only force is weight as drag is proportional to velocity, so the object accelerates downwards
• as it accelerates the velocity increases and the drag increases so there’s a smaller resultant force downwards (smaller acceleration)
• eventually, the object reaches a speed where the drag is equal to the weight meaning there is no acceleration (terminal velocity)

Question 14

how does extension vary with applied force on a spring?

Answer 14

• set up a clamp stand with a spring attached. attach a weight to the spring. make sure a ruler is behind to measure length.
• Measure the length of your spring without any hanging masses.
• Hang a mass of 100g on the spring
• Measure the new length of the spring
• Calculate the extension of the spring
• Repeat steps 3-5 with increasing mass in increments of 100g

Question 15

what is shown by a straight line on a force-extension graph?

Answer 15

Hooke’s law

Question 16

what is Hooke’s law?

Answer 16

extension is directly proportional to the force applied

Question 17

what is elastic behaviour?

Answer 17

• the ability of a material to recover its original shape after the force is removed
• in a spring this occurs when the force is lower than the elastic limit.