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4 years ago

MathPhys Pls see this Thank you in Advance MathPhys Is the best

Physics

2 answers:

storchak [24]4 years ago

8 0

Answer:

63.8

Explanation:

umka2103 [35]4 years ago

4 0

Answer:

70 N

21°

1.1 m/s²

Explanation:

Draw a free body diagram of the block. There are three forces:

Weight pulling straight down

Normal force pushing perpendicular to the incline

Friction force pushing parallel to the incline

Part 1

Sum the forces in the perpendicular direction:

∑F = ma

N − mg cos θ = 0

N = mg cos θ

The block is at rest, so F = N μs:

F = N μs

F = mg μs cos θ

F = (20 kg) (9.8 m/s²) (0.38) (cos 19°)

F = 70 N

Part 2

Sum the forces in the parallel direction (down the incline is positive):

∑F = ma

mg sin θ − F = 0

mg sin θ = N μs

mg sin θ = mg μs cos θ

tan θ = μs

θ = atan μs

θ = atan 0.38

θ = 21°

Part 3

Sum the forces in the parallel direction (this time, acceleration is not 0).

∑F = ma

mg sin θ − F = ma

mg sin θ − N μk = ma

mg sin θ − mg μk cos θ = ma

a = g (sin θ − μk cos θ)

a = (9.8 m/s²) (sin 24° − 0.32 cos 24°)

a = 1.1 m/s²

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3 years ago

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3 years ago

A 2.7 kg ball is thrown upward with an initial speed of 20.0 m/s from the edge of a 45.0-m-high cliff. At the instant the ball i

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Answer:

(a) At what angle above the horizontal should the ball be thrown so that the runner will catch it just before it hits the ground? (b) How far does the woman run before she catches the ball?

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Explanation:

see the attached file below

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3 years ago

A ball is thrown horizontally from a cliff at 8m/s .In what direction is the ball moving 2s later?

horrorfan [7]

Answer:

67.8 degrees below horizontal

Explanation:

In order to understand the direction of the ball after a certain time t, we need to find its horizontal and vertical components of the velocity.

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- Vertical component: the vertical component of the velocity of the ball is given by

vy = u + at

where

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vy = 0 + (-9.8 m/s^2)(2s )=-19.6 m/s

where the negative sign indicates it points downward.

So, the direction of the ball (given as angle below the horizontal) is:

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5 0

4 years ago