ANSEWR KEY
WORKSHEET 1b: FORCES
Qn Answer
2a
2b
As the angle X increases, the amount of pulling force needed to move the load
increases.
The force of 50 units is still needed to overcome friction between the load and
the plank when the plank was horizontal.
3a
3b
The bar magnet is strongest at its poles.
P was the magnet.
The magnetic force of attraction on Magnet P was the strongest at its poles thus
a strong force of attraction was felt when P was brought to the centre of Q.
4a
4b
P can be stretched more easily. When the same amount of load was placed
on both P and Q, P stretched more than Q.
4cm. The spring had been overloaded which resulted in a permanent extension
of 1cm. When there was no more load left, the new length of the spring is the
sum of its original length plus 1cm.
5a
5b
Use either wooden or glass surface only.
There was friction between the tray and the surface so heat was produced.
6a
As the wheelchair moves up the ramp, it is going against gravity. But when it is
moving down, the movement of wheelchair and gravitational pull is the same.
The raised parts increases friction between the surface and the wheels thus
preventing the wheelchair from sliding off the platform.
6b
7a
7b
8a
9b
The greater the height of the drop, the deeper the depth of the dent. The ball has
more gravitational potential energy at a greater height to be converted to more
kinetic energy as it drops, so the impact will be greater.
At a greater height, the objects possess greater gravitational potential energy
which will be converted into greater kinetic energy. The objects will drop with a
greater impact thus injuring the person.
The car still possesses some kinetic energy to move forward until all energy is
converted to heat/sound energy.
Or
There is still a push force exerted by the air released from the balloon.
Use a larger inflated balloon / blow more air into balloon
Add lubricant to the surface
Give the car a push