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3 years ago

-What can you say about the snowboarder’s kinetic energy as he moves?

Physics

1 answer:

Damm [24]3 years ago

7 0

Answer:

His kinetic energy increases, potential energy decreases

The sum of kinetic and potential energy is a constant at any instant before he comes to rest.

Explanation:

Snowboarder is starting from a height and moving to the down direction. As he moves down his velocity increases, we know that kinetic energy is given by the expression $\frac{1}{2} mv^2$ , so as he moves his kinetic energy increases.

When the snowboarder is starting his potential energy is maximum(Potential energy = mgh), as he comes down his potential energy decreases.

Based on this we can conclude that the sum of potential energy and kinetic energy is a constant at any instant for a snowboarder before he comes to rest.

mgh+ $\frac{1}{2} mv^2$ = Constant

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A rock is dropped from the top of a tall tower. Half a second later another rock, twice as massive as the first, is dropped. Ign

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B- the acceleration is greater for the more massive rock

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Sandy is on a road trip. She leaves at 8:00 AM. It takes her 2 hours to drive 200 kilometers. She stops at a rest stop for half

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The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:
$v= \frac{S}{t}$

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2 years ago

A chair exerts a force of 20 N on a floor and is not moving. What force does

AysviL [449]

The floor exerts 20 N of force on the chair

Explanation:

We can answer this question by using Newton's third law, which states that:

<em>"When an object A exerts a force (called action) on an object B, object B exerts an equal and opposite force (called reaction) on object A"</em>

In this problem, we can identify:

- Object A as the chair

- Object B as the floor

This means that the force of 20 N exerted by the chair on the floor is the action, and so the force exerted by the floor on the chair is the reaction. Newton's third law states that these two forces are equal and opposite: therefore, the force exerted by the floor on the chair is also 20 N, but in the opposite direction.

Learn more about Newton's third law:

brainly.com/question/11411375

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2 years ago

On the earth, when an astronaut throws a 0.250-kg stone vertically upward, it returns to his hand a time T later. On planet X he

Pachacha [2.7K]

Answer:

d) g/2

Explanation:

We need to use one of Newton's equations of motion to find the position of the stone at any time t.

x(t) = x₀(t) + ut - ¹/₂at²

Where

x₀(t) = initial position of the stone.

x(t) - x₀(t) = distance traveled by the stone at any time.

u = initial velocity of the stone

a = acceleration of the stone

t = time taken

On both planets, before the stone was thrown by the astronaut, x = 0 and t = 0.

=> 0 = x₀(t)

=> x₀(t) = 0

On earth, when the stone returns into the hand of the astronaut at time T on earth, x = 0.

=> 0 = 0 + uT - ¹/₂gT² (a = g)

=> uT = ¹/₂gT²

=> g = 2u/T

On planet X, when the stone returns into the hand of the astronaut, time = 2T , x = 0.

=> 0 = 0 + u(2T) - ¹/₂a(2T)²

=> 2uT = 2aT²

=> a = u/T

By comparing we see that a = g/2.

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3 years ago