Answer :
Answer:
a) F = 4666.67 N
b) F = 17500 N
c) See it into the explanation.
Explanation:
a) Given info
Mass of the arm, m = 7 Kg
Distance, d = 7.50 cm = 0.075 m
Initial speed, vi = 10.00 m/s
Final speed, vf = 0 m/s
Formulas used:
The work done is calculated by the equation
W = F*d ⇒ W = - 0.075*F
where F is the force
The kinetic energy is given by the formula
K = 0.5*m*v²
then
Ki = 0.5*m*vi² = 0.5*(7 Kg)*(10.00 m/s)² = 350 J
Kf = 0.5*m*vf² = 0 J
Calculation:
According to work-energy theorem we get
W = ΔK = Kf - Ki
⇒ - 0.075 m*F = 0 J - 350 J ⇒ F = 350 J / 0.075 m = 4666.67 N
b) Given info
Mass of the arm, m = 7 Kg
Distance, d = 2.00 cm = 0.02 m
Initial speed, vi = 10.00 m/s
Final speed, vf = 0 m/s
Formulas used:
The work done is calculated by the equation
W = F*d ⇒ W = - 0.02*F
where F is the force
The kinetic energy is given by the formula
K = 0.5*m*v²
then
Ki = 0.5*m*vi² = 0.5*(7 Kg)*(10.00 m/s)² = 350 J
Kf = 0.5*m*vf² = 0 J
Calculation:
According to work-energy theorem we get
W = ΔK = Kf - Ki
⇒ - 0.02 m*F = 0 J - 350 J ⇒ F = 350 J / 0.02 m = 17500 N
c) 17500 N > 4666.67 N
When making use of boxing gloves, the blow will be less painful for both the puncher and the hit. That is, the force of the blow is reduced by the material of the glove.
The gloves reduce the speed of the technique used by the boxer, but also protects them from strong blows.
Larger gloves offer more protection than small ones. The big ones are more padded than the little ones.
Being larger, the force of the blow on the impact takes longer to arrive, thus reducing the impact of the blow.
The force with the glove on is as if a 477 kg (1050 lb) mass were placed on the person’s face. That definitely could do damage, even though it is less than the effective 1790 kg mass of the force with no gloves.