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Basile [38]
3 years ago
15

A block of mass m slids up a ramp making an angle θ with the horizontal. The block has an initial KE of 1 2 m v2 0 as it starts

up the ramp and travels a distance L along the ramp before coming to momentary rest. v0 L How much work did kinetic friction do on the block between its starting point and the point it came to momentary rest?

Physics
1 answer:
Step2247 [10]3 years ago
5 0

Answer:

Explanation:

Given

mass of block is m

inclination of ramp is \theta

Initial kinetic energy \frac{1}{2}mv_0^2

Length of ramp is L

Block move a distance of L so it moves a vertical distance of L\sin \theta

Applying work Energy theorem i.e. change in kinetic energy of object is equal to work done by all the forces

Initial kinetic energy K.E._i=\frac{1}{2}mv_0^2

Final kinetic energy K.E._f=0

K.E._i-K.E._f=Work\ done\ by\ kinetic\ friction+work\ done\ by\ gravity

\frac{1}{2}mv_0^2=W_f+W_g

W_f=\frac{1}{2}mv_0^2-mgL\sin \theta

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Consider an elevator with a table and a book on top of the table. The mass of the table is 10kg and the mass of the book is 2kg.
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Newton's second law says that the net force is proportional to the product of the mass and the acceleration of the body

                Σ F = m a

Where the bold letters indicate vectors, m is the mass and the acceleration of the body

A free body diagram is a diagram where the forces are represented without the details of the bodies, in the attached we can see a free body diagram of the system.

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Let's write Newton's second law for each body

The book

                N₂ - W₂ + N₁ = m a

               

Table

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                W₁ = Mg

                W₂ = mg

                N₁ = (M + m) g + M a

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                N₁ = 152.6 N

This is the reaction of the earth to the support of the block and the table

               N₂ = ma + m g  - N₁

               N₂ = m ( a +g) - N₁  

               N₂ = 2 (3.5 + 9.8) - 152.6

               N₂ = 26.6 - 152.6

               N₂ = -126 N

The negative sign indicates that the direction is opposite to the one assigned, this is the action of the block on the table.

In conclusion using Newton's second law we can find the forces of the block on the table is 126 N

Learn more here: brainly.com/question/19860811

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b)

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