Given:
Initial speed of the motorcycle (u) = 35 m/s
Final speed of the motorcycle (v) = 0 m/s (Complete Stop)
Maximum deceleration of the motorcycle (a) = -1.2 m/s²
Required Equation:

Answer:
By substituting values in the equation, we get:

Time taken by motorcycle to come to a complete stop (t) = 29.167 s
As we know that friction force on box is given by

here we know that

here we have
m = 12 kg

so now we have

now we will have


so it required minimum 49 N(approx) force to move the block
Answer:
The ball has a potential energy of 53 J.
Explanation:
Mechanical energy, E = Kinetic energy + Potential energy
E = K.E + P.E
65 = 12 + P.E
P.E = 65 – 12
P.E = 53 J
Therefore the potential energy of the ball is 53 J