A large heavy rock, a medium size stone and a small marble are dropped at the same time from the roof of a building. Neglecting
2 answers:
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Use Newton's second law to determine the acceleration being applied to the sled. There are three forces at work on the sled (its weight, the force normal to the ground, and friction) but two of them cancel, leaving friction as the only effective force. This vector is pointed in the opposite direction of the sled's movement, so if we take the direction of its movement to be the positive axis, we would find the acceleration due to the friction to be
Now we use the formula
to find the distance it travels. The sled comes to a rest, so , and let's take the starting position
to be the origin. Then the distance traveled
is
Answer:
Compression of the spring: 0.18 m (downward)
Explanation:
The forces acting on the block of wood are:
- The force of gravity, acting downward, of magnitude , where m = 5.32 kg is the mass of the block and
is the acceleration due to gravity
- The force exerted by the spring, downward, of magnitude , where
is the spring constant and
is the elongation of the spring
- The buoyant force, upward, of magnitude , where
is the water density and V the volume of the block
Since the block is in equilibrium, the net force is zero, so we can write
(1)
We have to find the volume of the block first. We have:
m = 5.32 kg (mass)
(wood density)
So, the volume is
So now we can re-arrange eq.(1) to find the elongation of the spring, x:
So, the spring is compressed by 0.18 m.