As the centripetal force<span> acts upon an </span>object moving <span>in a </span>circle<span> at constant speed, the </span>force<span> always acts inward as the velocity of the </span>object<span> is directed tangent to the </span>circle. ... In fact, whenever the unbalanced centripetal force<span> acts perpendicular to the direction of </span>motion<span>, the speed of the </span>object will<span> remain constant.</span>
Diagram A is the correct diagram
The answer would be B. Magnetic fields are invisible they cannot be directly observed
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=

Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =

Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K



The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).