forces and their interactions (topic 5)

Question 1

contact or non-contact forces

Answer 1

Question 2

label the thrust, air resistance, weight, and normal reaction acting on the car as it accelerates long the horizontal road

Answer 2

Question 3

the car continues to accelerate at a decreasing rate until it reaches top speed, explain, with reference to the forces acting on the car, why a top speed is reached (3)

Answer 3

• air resistance increases
• resultant force decreases to zero
• car travels at constant speed when the resultant force acting on it is zero

Question 4

state what is meant by a vector quantity (1)

Answer 4

physical quantity with both magnitude/size and direction

Question 5

the cyclist decides to speed up and begins to pedal faster, the cyclist and bike have a mass of 110 kg, the cyclist has a thrust force of 205 N, resulting in an acceleration of 1.5 m/s^2, calculate the drag forces acting on the cyclist and bicycle

Answer 5

Question 6

label the forces acting on the ball as it accelerates towards the ground

Answer 6

Question 7

at the instant shown in the diagram, the air resistance is 0.4 N, the ball has a mass of 200 g, calculate the resultant force acting on the ball, the gravitational field strength on earth is 9.8 N/kg

Answer 7

Question 8

the weight of the ball is 2kg, as the ball falls, acceleration becomes zero, falling at terminal velocity, state the value of air resistance

Answer 8

2N, air resistance = weight of ball

Question 9

state the name of the force labelled A and B

Answer 9

• thrust or driving force
• air resistance or drag

Question 10

describe the motion of the cyclist, you should refer to the forces acting on the cyclist in your answer (2)

Answer 10

• the cyclist is accelerating
• thrust is greater than the air resistance

Question 11

force responsible for a sky diver reaching terminal velocity

Answer 11

air resistance