Which of the following has both kinetic and potential energy?
1 answer:
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Answer:
100 newtons
Explanation:
Given,
Jamal pushing a large box by a force, F = 100 N
Work done on the large box is, W = 0
It is because the applied force is less than the force of the friction between the two surfaces.
Yet, there will be a force that is exerted by the large box on Jamal.
According to newton's third law of motion, every action has an equal and opposite reaction. The reaction force is in the direction opposite to the force of action. But, their magnitude remains the same.
Hence, If the action force is 100 N, then the reaction force should be in 100 N
The horizontal distance covered by the ball before hitting the water is 70.4 m
Explanation:
The motion of the ball is the motion of a projectile, so it consists of two independent motions:
- A uniform motion along the horizontal (x) direction
- A uniformly accelerated motion along the vertical (y) direction
We start by calculating the time of flight of the ball. This can be done by analyzing the vertical motion. We can use the following suvat equation:
where:
s = -16.5 m is the vertical displacement of the ball (it is negative because we take upward as positive direction)
is the initial vertical velocity of the ball, which is given by
where
u = 23.5 m/s is the initial velocity
is the angle of projection
Substituting,
is the acceleration of gravity, downward
Substituting everything into the equation we get:
Solving the equation for t, we find the time of flight of the ball:
t = -0.94 s
t = 3.59 s
We ignore the 1st solution since it is negative, so the ball reaches the water after 3.59 seconds.
Now we analyze the horizontal motion of the ball. The horizontal velocity is constant and it is:
Therefore, the horizontal distance covered in a time t is
And substituting t = 3.59 s, we find
So, the horizontal distance covered by the ball before hitting the water is 70.4 m.
Learn more about projectile motion:
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