Answer:
B.
Explanation:
The elastic potential energy of the spriy at position 2 is converted to kinetic energy.
Answer:
The speed of stone traveling when it hits the ground = 49 m/s
Explanation:
Height of drop = 122.5 m
Given that distance the stone travels from its starting point
s(t) = 4.9t²
Substituting height
122.5 = 4.9t²
t² = 25
t = 5 seconds
So after 5 seconds stone hit the ground, we need to find velocity when t = 5 seconds.
Differentiating displacement with respect to time to get velocity,
s'(t) = 4.9 x 2 t = 9.8 t
Velocity when t = 5, s'(5) = 9.8 x 5 = 49 m/s
The speed of stone traveling when it hits the ground = 49 m/s
The verb you want is 'Calculate'.
Answer:
Assuming that air resistance is negligible.
a. Approximately .
b. Approximately .
Explanation:
Let denote the mass of this diver.
If the initial speed of the diver is , the initial kinetic energy () of this diver would be .
If the height of this diver is , the gravitational potential energy () of this diver would be .
The initial mechanical energy of this diver (sum of and ) would thus be: .
If air resistance on the diver is negligible, the mechanical energy of this diver would stay the same until right before the diver impacts the water. The entirety of the initial mechanical energy, , would be converted to kinetic energy by the time of impact.
Rearrange the equation to find an expression for the speed of the diver:
.
Thus, if the kinetic energy of the diver is , the speed of the diver would be:
.
Notice how , the mass of the diver was eliminated from the expression.
If the diver started with no initial speed () at a height of , the speed of the diver right before impact with water would:
.
If the diver started with an initial velocity of upwards (initial speed ) from a height of , the speed of the diver right before impact with water would be:
.