Momentum is conserved in a collision. Momentum is mass*velocity, so you can find your answer by calculating initial and final momentums and setting them equal to each other.
15kg * 3.50 m/s + 9kg * 2.35 m/s = 73.65 kg m/s
73.65 = 9 * 2.8 + 15x
solve for x
x= 3.23
The final velocity is 3.23 m/s
From the given problem, a limit on the depression of a building is placed at 20 centimeters. To solve how many floors can be safely added, a quantity of how many cm will a building sink for each floor that is added is needed. Unfortunately, it is not found anywhere in the problem. However, we can provide a formula to solve for the depression. This is as follows:
Building depression < 20 cm
Building depression = (cm depression per floor) * (no. of floors)
Answer:
A car moves up a hill at a constant velocity
Explanation:
Since the velocity is constant, the speed is also constant and so is the kinetic energy. However, total mechanical energy is sum of gravitational potential energy and kinetic energy, and the car is moving up the hill so its potential energy rises.
Thus, in the circumstances described the mechanical energy cannot be conserved.
The correct answer is A car moving up the hill with constant velocity.