Answer:
117.6 m/s downward
Explanation:
The penny is moving with uniform accelerated motion (free fall motion), so we can find its vertical velocity at time t with the following suvat equation:
v = u + at
where
v is the velocity at time t
u is the initial velocity
a is the acceleration
The penny starts at rest, so
u = 0
Also, the acceleration is the acceleration of gravity,
where we have chosen upward as positive direction, so the acceleration is negative, since it is downward.
Substituting t = 12 s, we find the velocity of the penny when it hits the ground:
downward, since the sign is negative.
Answer:
D
Explanation:
Hooke's law states the force exerted by a spring is the product of its spring constant and its displacement.
F = kx
Solving for the spring constant:
k = F/x
All the springs are pulled with equal force (the weight of the mass), so the spring with the smallest displacement has the largest spring coefficient.