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OleMash [197]
3 years ago
7

A 4.0-m-diameter playground merry-go-round, with a moment of inertia of

Physics
1 answer:
HACTEHA [7]3 years ago
5 0

Answer:

7.1 ms⁻¹

Explanation:

d = diameter of merry-go-round = 4 m

r = radius of merry-go-round = \frac{d}{2} =  \frac{4}{2} = 2 m

I = moment of inertia = 500 kgm²

w_{i} = angular velocity of merry-go-round before ryan jumps = 2.0 rad/s

w_{f} = angular velocity of merry-go-round after ryan jumps = 0 rad/s

v = velocity of ryan before jumping onto the merry-go-round

m = mass of ryan = 70 kg

Using conservation of angular momentum

Iw_{i} - m v r = (I + mr^{2})w_{f}

(500)(2.0) - (70) v (2) = (I + mr^{2})(0)

1000 = 140 v

v = 7.1 ms⁻¹

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a golfer hits a golf ball with a velocity of 36.0 meters/second at an angle of 28.0. if the hang time of the golf ball is 33.4 s
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since there are no horizontal forces acting on the ball, there are no horizontal accelerations and the initial horizontal velocity of 36 cos 28 will be constant throughout. If we use the correct time of flight given the launch parameters, we have 

range = 36 cos 28 x 3.44 s = 109.3 m

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Goal posts at the ends of football fields are padded as a safety measure for players who might run into them. How does thick pad
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The answer given by E2020 is

"The padding around the goal post increases the time of the collision between the player and the post, which decreases the force exerted to bring the player to a stop"

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A solid cylinder of mass 7 kg and radius 0.9 m starts from rest at the top of a 20º incline. It is released and rolls without sl
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Answer:

157.8 J

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PE = Gravitational potential energy at the top

Using conservation of energy

Total Energy at the bottom = Gravitational potential energy at the top  

TE = PE

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3 years ago
A toy gun uses a spring to project a 4.5-g soft rubber sphere horizontally. The spring constant is 8.0 N/m, the barrel of the gu
marishachu [46]

Answer:

1.93 m/s

Explanation:

Parameters given:

Mass = 4.5g = 0.0045kg

Spring constant = 8.0 N/m

Length of barrel = 13 cm = 0.013m

Frictional force = 0.035N

Compression = 5.8 cm = 0.058m

First, we find the P. E. stored in the spring:

P. E. = ½*k*x²

P. E. = ½ * 8 * 0.058² = 0.013J

Then, we find the work done by the frictional force while the sphere is leaving the barrel of the gun:

Work = Force * distance

The distance here is the length of the barrel.

Work = 0.035 * 0.13 = 0.0046 J

The kinetic energy of the sphere can now be found:

K. E. = P. E. - Work done

K. E. = 0.013 - 0.0046 = 0.0084J

We can now find the speed using the formula for K. E.:

K. E. = ½*m*v²

0.0084 = ½ * 0.0045 * v²

v² = 0.0084/0.00255 = 3.733

=> v = 1.93 m/s

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3 years ago
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