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3 years ago

You push very hard on a heavy desk, trying to move it. You do work on the desk:

Physics

1 answer:

frozen [14]3 years ago

3 0

Answer:

Explanation:

We know that work done is given by

$W=F.d=Fdcos\Theta$

So there are two case in which work done is zero

First case is that when force and displacement are perpendicular to each other

And other case is that when there is no displacement

So for work to be done there must have displacement, if there is no displacement then there is no work done

So option (c) will be the correct option

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It takes 200 N to move a box 10 meters in 8 seconds. How much power is

svetoff [14.1K]

Answer:

Explanation:

The equation of power is defined as Power = Workdone/Time Taken

And workdone = Force x Distance so using these equations we get they workdone is, 200x 10 = 2000Nm.

Dividing workdone with time will yield power, 2000 ÷ 8 = 250 Nm/s = 250W.

8 0

3 years ago

Please help! i'm horrible at this

frez [133]

Answer:

a = Δv/t = (vf - vi)/t = (0 - 5)/4 = -1.25 m/s²

Explanation:

You may or may not need the negative sign, depending on how the question designer was thinking about the problem.

4 0

3 years ago

Two separate masses on two separate springs undergo simple harmonic motion indefinitely (the surface is frictionless). In CASE 1

Artemon [7]

Answer:

$\frac{F_1}{F_2} =\frac{1}{2}$

Explanation:

Assuming the we have to find ratio maximum forces on the mass in each case

we know that in a spring mass system

F= Kx

K= spring constant

x= spring displacement

Case 1:

$F_1=2k\times d$

case 2:

$F_2=2k\times 2d$

therefore, $\frac{F_1}{F_2} = \frac{2K\times d}{2K\times 2d}$

$\frac{F_1}{F_2} =\frac{1}{2}$

4 0

3 years ago

Jack rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on th

mote1985 [20]

Answer: D

Height of marble from ground

Explanation:

From the formula of kinetic energy and potential energy,

K.E = 1/2mv^2

While

P.E = mgh

From all the parameters given from the question. You can see that mass is constant, acceleration due to gravity is also constant.

Independent variable must be a value that can varies.

Since Jack rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on the ramp to see the effects on both energies.

This different position must be the height which will produce an effect on the potential and kinetic energy of the marble.

Independent variable always provides an effect for dependent variable. Which are kinetic energy and potential energy in this case.

Height of marble from ground is the right answer.

6 0

3 years ago

Say you want to make a sling by swinging a mass M of 1.9 kg in a horizontal circle of radius 0.042 m, using a string of length 0

padilas [110]

Answer: T= 715 N

Explanation:

The only external force (neglecting gravity) acting on the swinging mass, is the centripetal force, which. in this case, is represented by the tension in the string, so we can say:

T = mv² / r

At the moment that the mass be released, it wil continue moving in a straight line at the same tangential speed that it had just an instant before, which is the same speed included in the centripetal force expression.

So the kinetic energy will be the following:

K = 1/2 m v² = 15. 0 J

Solving for v², and replacing in the expression for T:

T = 1.9 Kg (3.97)² m²/s² / 0.042 m = 715 N

3 0

3 years ago