Explanation:
Contact force is any force that requires contact. An object that exerts a force on another object by touching it is exerting a contact force. Examples of contact force are friction and normal force.
Examples of a non-contact force are gravity and magnetism.
Answer:

Explanation:
Let consider a car travelling at a speed
. The ratio of final kinetic energy to initial kinetic energy:


The final speed is:

Answer:
The value is 
Explanation:
From the question we are told that
The velocity is
[/tex]
The time taken is 
The time taken for contact is 
The velocity of the of the car after contact is
[/tex]
From the equation of kinematics we have that

Here u = 0 \ m/s since the car is initially motionless
=> 
=> 
Answer:
The magnetic field of a magnet any magnet is stronger at the poles, so the poles have a bigger magnetic field which types: bar magnetics and etc.hope this helps