A car has a mass of 900 kg It accelerates from rest at a rate of 1.2 m/s2
a Calculate the time taken to reach a velocity of
30 m/s
b Calculate the force required to accelerate the car
at a rate of 1.2 m/s
[3]
c Even with the engine working at full power, the
car's acceleration decreases as the car goes faster
Why is this?
[3]
5 The diagram below shows some of the forces acting
on a car of mass 800 kg
)
direction of motion
nuing force
2000 N
total drag force
a State the size of the total drag force when the car
is travelling at constant speed.
b The driving force is increased to 3200 N.
í Find the resultant force on the car at this
instant
ü Write down, in words, the equation
connecting mass, force and acceleration,
iii Calculate the initial acceleration of the car. [2]
c Explain why the car will eventually reach a new
higher constant speed.
[2]
6
3N
4N
a Using a scale drawing (for example, on graph
paper), find the resultant of the forces above. [5
b Draw diagrams to show how, by changing the
direction of one of the forces, it is possible to
produce a resultant of i 7N, 1N