when a book falls from a shelf to the ground without anyone pushing on it, no work is done to the book. True or False
1 answer:
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Let the mass of 2500 kg car be and it's velocity be
and the mass of 1500 kg car be
and it's velocity be
.
After the bumping the mass be M and it's velocity be V.
By law of conservation of momentum we have
2500 * 5 + 1500 * 1=4000 * V
V = 14000/4000 = 7/2 = 3.5 m/s
So the velocity of the two-car train = 3.5 m/s
Answer:
Mass = 18.0 kg
Explanation:
From Hooke's law,
F = ke
where: F is the force, k is the spring constant and e is the extension.
But, F = mg
So that,
mg = ke
On the Earth, let the gravitational force be 10 m/.
3.0 x 10 = k x 5.0
30 = 5k
⇒ k = ................ 1
On the Moon, the gravitational force is of that on the Earth.
m x = k x 5.0
= 5k
⇒ k = ............. 2
Equating 1 and 2, we have;
=
m =
= 18.0
m = 18.0 kg
The mass required to produce the same extension on the Moon is 18 kg.