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3 years ago

A horizontal force of 300.0 N is used to push a 145-kg mass 30.0 m horizontally in 3.00 s. Calculate the power developed.

Physics

1 answer:

Svetradugi [14.3K]3 years ago

4 0

Answer:

3 * 10³J/s

Explanation:

Given :

Force applied, F = 300 N

Distance, d = 30 m

Time, t = 3 seconds

Power, P = Workdone / time

Recall :

Workdone = Force * distance

Workdone = 300 N * 30 m = 9000 Nm

Workdone = 9 * 10³ J

Power = (9 * 10³ J) / 3s

Power = 3 * 10³J/s

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Answer:

Explanation:

Given that the weight of the crate is

M=48kg

Then, weight of boy is

W=mg=48×9.8=470.4N

ΣF = ma ,Along y axis

Since the body is not moving in y direction then, a=0 along y axis

N-W=0

N=W

The normal equals weight of boy

N=470.4N

Then, applying frictional force opposing the boy motion.

Fr=μN

Fr=0.5×470.4

Fr=235.2N

Then, this is the forward force that the boy try using to pull the crate.

Since he can barely move his foot he has not yet overcome the coefficient of static friction.

ΣF = ma. , along x-axis

a along x-axis is 0 since he cannot move his foot, I.e he was not moving

F-Fr= 0

F=Fr=235.2N

The forward force the boy apply is 235.2N on the crate

Also, analysing the crate.

The forward force is now F=235.2N

Then the frictional force =Fr

Then,

ΣF = ma. , along x-axis

a along x-axis is 0 since the crate did not move,

F-Fr=0

Fr=F=235.2N

This is the frictional force on the crate.

Then using frictional law

Fr=μN

N=Fr/μ

N=235.2/0.9

N=261.33N

Now this normal is equal to the weight of the crate

ΣF = ma ,Along y axis

Since the body is not moving in y direction then, a=0 along y axis

N-W=0

W=N=261.33N

Then, since weight is given as

W=mg

m=W/g

m=261.33/9.81

m=26.64kg

The mass of the crate is 26.64kg

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3 years ago

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On a cold winters day if you left a cup of water sitting outside it could freeze heat is transferred out of the water describe t

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The water molecules would slow down, and as they slow down, the heat created from their movement would cease.

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3 years ago

A 2200 kg SUV traveling at 23.9 m/s can be stopped in 0.16 s if it hits a concrete wall. Assume that a 60 kg person was in the c

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Answer:

8962.5 N

Explanation:

From fundamental kinematics equations, acceleration, a is given by $a=\frac {v-u}{t}$ where v is final velocity, u is initial velocity and t is time

We also know that force is a product of mass and acceleration of an object and substituting $a=\frac {v-u}{t}$ in the formula F=ma we obtain

$F=ma=m\frac {v-u}{t}$ where m is the mass of the body

$F=60\times\frac {0-23.9}{0.16}=-8962.5 N$

Therefore, the force is 8962.5 N

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4 years ago

2. What is the kinetic energy of a 7.26 kg bowling ball that is rolling at a speed of 2 m/s?

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Inserting the values in formula gives:

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14.52J

This is the final answer which gives the kinetic energy of the ball.

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