Speed and Acceleration
What is the standard SI unit used to measure speed?
Metres per second (m/s)
What single force acts downwards on all objects near the Earth's surface due to gravity?
Weight .
Name the force that always opposes motion between two surfaces sliding past each other.
Friction.
What is meant by the quantity mass?
the amount of matter in an object
How long will it take a train travelling at a constant speed of 25 m/s to cover a distance of 1,000 metres?
40 s
Calculate the speed of a car that travels 2.5km in 2 minutes.
20.8 m/s
State the unit used to measure force.
Newtons N
State whether this statement is True or False: "Air resistance on a moving vehicle decreases as the vehicle speeds up."
False (air resistance increases as speed increases).
State whether this statement is True or False: "Your mass would change if you travelled to the Moon, but your weight would stay the same."
False (mass remains constant everywhere, while weight changes depending on gravitational field strength).
A skydiver's speed increases from 10 m/s to 35 m/s over 5 seconds. Calculate their average acceleration.
5 m/s^2
State whether this statement is True or False: "If an object is moving at a constant speed, its acceleration must be zero."
True (acceleration is the rate of change of speed/velocity; constant speed means zero change).
A box is pulled to the right with a force of 200N and pushed to the left with a force of 52N. What is the resultant force and its direction?
148N to the right
Name 3 non-contact forces.
Magnetic, electrostatic, weight (gravity)
On Earth, the gravitational field strength g is 9.81 m/s^2. Calculate the weight of an 80kg astronaut on Earth.
784.8 N
A car accelerates from rest at a rate of 3 m/s^2 for 6 seconds. Calculate its final speed.
18m/s
A sprinter accelerates from rest to a velocity of 8.5m/s over a period of 2.3s. What is their acceleration?
3.70 m/s^2
State whether this statement is True or False: "An object with balanced forces acting on it must be stationary."
False (balanced forces mean zero resultant force, so the object can be stationary or moving at a constant speed in a straight line).
Explain why a skydiver eventually reaches terminal velocity after jumping from an airplane.
As speed increases, upward air resistance increases until it equals the downward weight force. The resultant force becomes zero, so acceleration stops and speed remains constant.
The gravitational field strength on the Moon is 1.6 N/kg. Calculate the weight of the same 80kg astronaut on the Moon.
128N
A bus decelerates at a rate of 2 m/s^2 to come to a complete stop (0 m/s). If its initial speed was 16 m/s, how many seconds did it take to stop?
8
A cyclist travels at 12m/s for 3 minutes. Calculate the total distance covered in km.
2.16km
A rocket has a mass of 500kg. The engines produce an upward thrust of 7000N. Taking gravitational field strength g = 10N/kg, calculate the resultant upward force on the rocket.
2000N upwards
A toy car of mass 0.2kg experiences 3N of air resistance and 2N of surface friction while its motor provides 8N of driving force. Calculate the resultant forward force on the car and the resulting acceleration.
3N forward
15m/s^2
An unknown planet exerts a gravitational force of 450N on a 30kg rover. What is the gravitational field strength g on this planet?
15 N/kg
A car with a mass of 1,200 kg is accelerated by a resultant forward force of 3,000 N for 8 seconds until it reaches a final speed of 30 m/s. Calculate the car's initial speed.
10m/s