Hello!

Use the equation for momentum:

Plug in the given mass and velocity into the equation:


That's unaccelerated motion,
and constant velocity.
C.There is an invisible magnetic field around the magnet where it exerts magnetic force
Yes an object in motion has kinetic energy
Answer:
180 m
Explanation:
Case 1.
U = 40 km/h = 11.1 m/s, V = 0, s = 20 m
Let a be the acceleration.
Use third equation of motion
V^2 = u^2 + 2 as
0 = 11.1 × 11.1 - 2 × a × 20
a = 3.08 m/s^2
Case 2.
U = 220 km/h = 33.3 m/s, V = 0
a = 3.08 m/s^2
Let the stopping distance be x.
Again use third equation of motion
0 = 33.3 × 33.3 - 2 × 3.08 × x
X = 180 m