Forces and their effects

Indicate which of these phenomena are produced by forces at a distance and which are produced by forces through contact:
a) The motion of a train due to magnetic levitation.
b) The deformation of a spring when a weight is attached to it.
c) The skidding of a car on a pool of water.
d) The formation of the aurora borealis.
e) The motion of a cupboard when pushed.

Classify the following objects into rigid, plastic or elastic bodies:
a) The mechanism of a key on the computer keyboard.
b) Sunglasses.
c) A headband.
d) A steel fork.
e) The bristles of a toothbrush.
f) Bread dough.

A car is moving in a straight path, covering 3 600 meters in 90 seconds. Determine the speed of the car, expressed in km/h.

A car is increasing its speed from 40 m/s to 70 m/s. What is its acceleration if the time needed was 3 seconds?

If the speed of a car is 75 km/h. How long does it take the car to cover a distance of 75 km?

The speed of blood flow is 30 cm/s. Considering a vein as a straight path, how long will it take for blood to cover a distance of 30 cm?

There are 150 000 000 km between the Sun and the Earth. If the velocity of light in a vacuum is 300 000 km/s, how long does it take for light to reach the Earth?