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3 years ago

5

there were 5 seconds left in a basketball game. In order to run out the clock a player threw the ball directly up as hard as he

could. How hard would the player have to throw the ball to make sure that it would not land before time expired? Hint: d= -16t + vt+ h

1 answer:

spin [16.1K]3 years ago

7 0

Answer:

80

Explanation:

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Average atomic mass of carbon is 12.01 amu

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3 years ago

Your backpack has a mass of 8 kg. You drop it from a height of 1.3m. How much work is done by gravity as the backpack falls?

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Answer:

The answer is C.

Explanation:

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3 years ago

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You may have noticed runaway truck lanes while driving in the mountains. These gravel-filled lanes are designed to stop trucks t

Sladkaya [172]

Answer:

0.767

Explanation:

The work done on the truck by the frictional drag force is given by

$W=-Fd$

where

F is the magnitude of the frictional force

d = 38.0 m is the maximum displacement allowed for the truck

The negative sign is due to the fact that the force of friction is opposite to the motion of the truck

The force of friction can also be written as:

$F=\mu mg$

where

$\mu$ is the coefficient of kinetic friction between the truck and the lane

m is the mass of the truck

g is the acceleration of gravity

So we can rewrite the work done as

$W=-\mu mg d$ (1)

According to the work-energy theorem, the work done by friction is equal to the change in kinetic energy of the truck:

$W=K_f - K_i = \frac{1}{2}mv^2-\frac{1}{2}mu^2$ (2)

where

v = 0 is the final velocity of the truck

u = 23.9 m/s is the initial velocity of the truck

By combining (1) and (2) we get

$-\frac{1}{2}mu^2 = -\mu mg d$

And solving for $\mu$ , we find the minimum coefficient of kinetic friction able to stop the truck in a distance d:

$\mu = \frac{u^2}{2gd}=\frac{23.9^2}{2(9.8)(38.0)}=0.767$

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3 years ago

Which 3 components must be used in order for a light bulb to light?

crimeas [40]

Answer:

a,e,d

Explanation:

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3 years ago

You are an engineer in charge of designing a new generation of elevators for a prospective upgrade to the Empire State Building.

DanielleElmas [232]

Answer:

t_total = 23.757 s

Explanation:

This is a kinematics exercise.

Let's start by calculating the distance and has to reach the limit speed of

v = 18.8 m / s

v = v₀ + a t₁

the elevator starts with zero speed

v = a t₁

t₁ = v / a

t₁ = 18.8 / 2.40

t₁ = 7.833 s

in this time he runs

y₁ = v₀ t₁ + ½ a t₁²

y₁ = ½ a t₁²

y₁ = ½ 2.40 7.833²

y₁ = 73.627 m

This is the time and distance traveled until reaching the maximum speed, which will be constant throughout the rest of the trip.

x_total = x₁ + x₂

x₂ = x_total - x₁

x₂ = 373 - 73,627

x₂ = 299.373 m

this distance travels at constant speed,

v = x₂ / t₂

t₂ = x₂ / v

t₂ = 299.373 / 18.8

t₂ = 15.92 s

therefore the total travel time is

t_total = t₁ + t₂

t_total = 7.833 + 15.92

t_total = 23.757 s

6 0

3 years ago