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White raven [17]
3 years ago
9

A boy throws a ball vertically up and catches it after 3 s. What height did the ball reach?

Physics
2 answers:
Crazy boy [7]3 years ago
7 0

Answer:

11.025 meters

Explanation:

The gravity’s acceleration on the surface of earth is approximately 9.8m/s

If it took 3 s to go up and come back, that means it took (1/2) × 3 to go from his hand to its highest point, and that amount of time again (1.5 seconds) to go back down to his hand.

This means the ball accelerated from Vi (initial Velocity) to 0 in 1.5 s

To find g in 1.5 i.e speed =

1.5 × 9.8 m/s = 14.7 m/s.

To find the height the ball reached=

We will use d = rt for this. Distance = Rate × Time

Since, it went 14.7 m/s at the start, and 0 m/s at the top, so the average speed of the ball going upward was (0+14.7)/2 = 7.35 m/s

7.35 m/s was the average speed = rate.

Time was 1.5 seconds, so we multiply.

7.35 m/s × 1.5seconds = 11.025 meters

Darya [45]3 years ago
3 0
The top height the ball had is (9/8)*g
g being the strength of the earth's attraction. so if g is about 9.8 then the ball went up about 11 meters
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3 years ago
In a pickup game of dorm shuffleboard, students crazed by final exams use a broom to propel a calculus book along the dorm hallw
RSB [31]

Answer:

The coefficient of kinetic is

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Explanation:

The forces in the axis 'x' and 'y' using law of Newton to find coefficient of kinetic friction

ΣF=m*a

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ΣFy=Fn-Fu=m*a

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F_{N}-F_{u}=m*a\\F_{N}-u_{k}*N=m*a\\u_{k}*N=F_{N}-m*a\\u_{k}=\frac{F_{N}-m*a}{N}

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v_{f} ^{2}=v_{o}^{2}+2*a(x_{f}-x_{o})\\x_{o}=0\\v_{o}=0\\v_{f} ^{2}=2*a*x_{f}\\a=\frac{v_{f} ^{2}}{2*a*x_{f}}\\ a=\frac{(1.53\frac{m}{s} )^{2}}{2*0.91m}\\a= 1.28 \frac{m}{s^{2} }

So replacing the acceleration can fin the coefficient:

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5 0
3 years ago
Two wheels having the same radius and mass rotate at the same angular velocity. One wheel is made with spokes so nearly all the
Mazyrski [523]

Answer:

C. The wheel with spokes has about twice the KE.

Explanation:

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radius = r

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Angular speed = ω

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KE=\dfrac{1}{2}I\omega ^2

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Now by comparing kinetic energy

\dfrac{KE_1}{KE_2}=\dfrac{I_1}{I_2}

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5 0
3 years ago
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Anvisha [2.4K]

Answer:

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