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Answer:
the resistance that one surface or object encounters when moving over another.
Explanation:
Answer:
A
Explanation:
Given that a stone dropped from the top of a 80m high building strikes the ground at 40 m/s after falling for 4 seconds. The stone's potential energy with respect to the ground is equal to its kinetic energy. (use 9 - 10 m/s)
O at the moment of impact
2 seconds after the stone is released after the stone has fallen 40 m
when the stone is moving at 20 m/s
At the top of the hill, the P.E = mgh
P.E = 10 × 80 × m
P.E = 800m
At the moment of impact, K.E = 1/2mv^2
K.E = 1/2 × 40^2 × m
K.E = 1/2 × 1600 × m
K.E = 800m
Since both P.E and K.E are the same, we can therefore conclude that the stone's potential energy with respect to the ground is equal to its kinetic energy at the moment of impact.
The correct answer is option A.
Acceleration = (force) / (mass)
If there is no friction . . .
Acceleration = (200N) / (50 kg) = 4m/s²
Change in speed = (acceleration) x (time) = (4 m/s²) x (10 sec) = 40 m/s
<em>Final speed = (speed of the cart before the force began) + (40 m/s more)</em>
(That's about <em><u>89 mph faster</u></em> than the cart was moving before the force started.)
In order to escape the gravitational pull of our planet, any object must have an escape velocity of 7 km/s or more, anything lower than that will be slowed down by the pull of gravity, and will eventually returned to the surface of our planet. It is independent of mass, any lighter or heavier object must attain the required escaped velocity to reach space.
