Answer:
400 N
Explanation:
Change of Kinetic Energy to Friction Wok
∆KE = W
½ x m x (v(5)² - v(3)²) = f x d
½ x 500 x (5² - 3²) = f x 10
250 x (25 - 9) = f x 10
25 x 16 = f
f = 400 N
Answer:
B
Explanation:
When air is heated, it expands and rises.
Answer:
The lighter frog goes higher than the heavier frog.
The lighter frog is moving faster than the heavier frog
Explanation:
If both frogs have the same kinetic energy when they leave the ground, the following equality applies:

Now, if the only force acting on the frogs is gravity, when they reach to the maximum height, we can apply the following kinematic equation:

When h= hmax, the object comes momentarily to an stop, so vf =0
Solving for hmax:

As the lighter frog, in order to have the same kinetic energy than the heavier one, has a greater initial velocity, it will go higher than the other.
As a consequence of both having the same kinetic energy, the lighter frog will be moving faster than the heavier frog.