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densk [106]
3 years ago
8

A 1000 kg car is rolling slowly across a level surface at 1m/s, heading toward a group of small innocent children.

Physics
2 answers:
Ne4ueva [31]3 years ago
7 0

Answer:

The force is -1620.73 N.

Explanation:

Given that,

Mass of car = 1000 kg

Velocity = 1 m/s

Distance = 2 m

Angle = 30°

We need to calculate the force

Using formula of work done

W_{net}=K_{f}-K_{i}

F\times d=K_{f}-K_{i}

Fd\cos\theta=-K_{i}

F=\dfrac{-K_{f}}{d\cos\theta}

F=-\dfrac{\dfrac{1}{2}mv^2}{d\cos\theta}

Put the value into the formula

F=-\dfrac{\dfrac{1}{2}\times1000\times(1)^2}{2\times\cos30}

F=-1620.73\ N

Hence, The force is -1620.73 N.

AnnyKZ [126]3 years ago
4 0

Answer:

Force, F = 288.67 N

Explanation:

Mass of the car, m = 1000 kg

Initial speed of the car, u = 1 m/s

The car and push on the hood at an angle of 30° below horizontal, \theta=30^{\circ}

Distance, d = 2 m

Let F is the force must you push to stop the car. using work energy theorem to find it. According to this theorem, the work done is equal to the change in kinetic energy as :

W=\dfrac{1}{2}m(v^2-u^2)

F\times d=\dfrac{1}{2}m(v^2-u^2)

It stops, v = 0

Fd\ cos\theta=\dfrac{1}{2}m(u^2)      

F=\dfrac{\dfrac{1}{2}m(u^2)}{d\ cos\theta}

F=\dfrac{\dfrac{1}{2}\times 1000\times (1)^2}{2\ cos(30)}

F = -288.67 N

So, the force required to push to stop the car is 288.67 N. Hence, this is the required solution.                                            

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Glycerin is poured into an open U-shaped tube until the height in both sides is 20 cm. Ethyl alcohol is then poured into one arm
lina2011 [118]

Answer:

Difference in height = 7.5 cm

Explanation:

We are given;.

Height of ethyl alcohol;h2 = 20 cm = 0.2 m

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g will cancel out to give;

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h1 = 0.125 m

Difference in height will be;

Δh = h2 - h1

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Δh = 0.075 m = 7.5 cm

4 0
3 years ago
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balu736 [363]

The fact that the layers of graphite are held together by only weak Van der Walls forces implies that they can slide over each other.

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3 0
2 years ago
which statement is a Hypothesis? A: Most of the earthworms moved to the shaded area during experiment. B: If an earthworm is giv
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Answer:

B

Explanation:

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3 0
3 years ago
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viva [34]
Statement B is correct.
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A hoop (I = MR2) of mass 3 kg and radius 1.1 m is rolling at a center-of-mass speed of 11 m/s. An external force does 842 J of w
Scilla [17]

Answer:

v_f = 20 m/s

Explanation:

Since the hoop is rolling on the floor so its total kinetic energy is given as

KE = \frac{1}{2}mv^2 + \frac{1}{2} I\omega^2

now for pure rolling condition we will have

v = R\omega

also we have

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