Answer:
a) 10 seconds
b) 100 meters
Explanation:
<u>Accelerated Motion
</u>
If an object is moving at contant speed, we know it has zero net force applied. As soon as an unbalanced force appears, the object accelerates (positive or negative) depending on the direction of the force with respect to movement. The speed of an object subject to acceleration is given by
The distance traveled is given by
a)
Our train is travelling at 20m/s when it decelerates at 
(negative for it's against movement). If nothing else happens, it will eventually stop (
). We can compute the time at which it happens
:
b)
The distance traveled is
What is the unit c denotes here
Do you know what's this unit called? it may help figure out how to do it.
Answer:
Explanation:
In order to solve this problem, we can do an analysis of the energies involved in the system. Basically the addition of the initial potential energy of the spring and the kinetic energy of the mass should be the same as the addition of the final potential energy of the spring and the kinetic energy of the block. So we get the following equation:
In this case, since the block is moving from rest, the initial kinetic energy is zero. When the block loses contact with the spring, the final potential energy of the spring will be zero, so the equation simplifies to:
The initial potential energy of the spring is given by the equation:
the Kinetic energy of the block is then given by the equation:
so we can now set them both equal to each other, so we get:
This new equation can be simplified if we multiplied both sides of the equation by a 2, so we get:
so now we can solve this for the final velocity, so we get:
