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2 years ago

Calculate the power of a person that does 8kJ of work in 4 hours

Physics

2 answers:

telo118 [61]2 years ago

7 0

Answer:

Explanation:

Energy used is power multiplied by time.

Power is energy used divided by time

8 kj is 8000 j

4 hours is 240 minutes

240 minutes is 14400 seconds

8000j divided by 14400 is 0.55 recurring, measured in watts

anzhelika [568]2 years ago

3 0

$\text{Power,}~ P = \dfrac{\text{Work done}}{\text{Time}}\\\\\\~~~~~~~~~~~~~=\dfrac{8 \times 1000~J}{4 \times 3600~ s}\\\\\\~~~~~~~~~~~~~~=\dfrac{80}{144}\\\\\\~~~~~~~~~~~~~~=0.56~ W$

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If a 990 kg car is on the road and the Ff is 360 n what is the normal force

Veseljchak [2.6K]

Given that a car is in the road, there is only movement in the x-direction. There is no movement in the y-direction.

Looking at the y-direction for the normal force:

F = N - mg
0 = N - mg, (no movement in y-dir.)
N = mg
N = (990)(9.8)
N = 9702 newtons

The normal force exerted on the car by the road is 9702 newtons.

8 0

2 years ago

Read 2 more answers

Several students measured the motion of a remote control car. They recorded the data in the following chart.

Rainbow [258]

A)At 5.5sec car is at rest because the distance is same as at 5.0sec .

B) At t= 2sec where the distance covered by a car is 20m.

The speed of the car is 10m/s

C) Average speed

4/Savg= 0.14+6.4+5.8+5p.27

Savg = 0.227 m/s

What is non uniform motion ?

When the object is moving with unequal distance along with unequal time intervals.

to learn more about Motion click brainly.com/question/18345181

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5 0

9 months ago

A 2kg mass is suspended on a rope that wraps around a frictionless pulley attached to the ceiling with a mass of 0.01kg and a ra

worty [1.4K]

Answer:

The torque on the pulley, when the system is motionless is approximately 9.81 N·m

Explanation:

The given parameters are;

The mass of the object = 2 kg

The friction between the rope and the pulley = 0

The mass of the rope, $m_r$ = 0.5 kg

The mass of the pulley, $m_p$ = 0.01 kg

The radius of the pulley, r = 0.25 m

The torque on the pulley, τ = I·α = F × D

The torque on the pulley, when the system is motionless, τ = F × D

Where;

F = The force acting on the pulley rope = The weight of the mass ≈ 2 kg × 9.81 m/s² = 19.62 N

D = The diameter of the pulley = 2×r = 2 × 0.25 m = 0.5 m

Therefore;

τ = 19.62 N × 0.5 m = 9.81 N·m

The torque on the pulley, when the system is motionless, τ ≈ 9.81 N·m.

4 0

2 years ago

A top of rotational inertia 4.0 kg m2 receives a torque of 2.4 nm from a physics professor. the angular acceleration of the body

Tanzania [10]

Angular acceleration is simply the ratio of the Torque over the rotation inertia, that is:

Angular acceleration = Torque / Rotational inertia

So substituting the values:

Angular acceleration = 2.4 N m / 4.0 kg m2

<span>Angular acceleration = 0.7 rad/s^2</span>

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:

Given that

Mass , radius and the angular speed for both the wheels are same.

radius = r

Mass = m

Angular speed = ω

The angular kinetic energy KE given as

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

I=Moment of inertia for wheels

Wheel made of spokes

I₁ = m r²

Wheel like a disk

I₂ = 0.5 m r²

Now by comparing kinetic energy

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

$\dfrac{KE_1}{KE_2}=\dfrac{mr^2}{0.5mr^2}$

$\dfrac{KE_1}{KE_2}=2$

KE₁= 2 KE₂

Therefore answer is C.

5 0

2 years ago