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3 years ago

100 POINTS! PLEASE HELP!

Physics

2 answers:

bagirrra123 [75]3 years ago

8 0

Answer:

By the information given, I am not sure how the event has played out. However, using common knowledge, I can give a scenario of how it may play out.

When removing the first block (the foundation), gravity will pull the other blocks down, as the strength of gravity exceeds that of the strength of air holding it up. This means that all the blocks on top would fall.

By definition of Newton's 1st - 3rd laws, the blocks would not move unless a force is given to it (i.e., removing the bottom block, which causes gravity). Gravity would pull the other blocks downwards. This would lead to the falling of the stack of blocks.

vaieri [72.5K]3 years ago

8 0

Answer:

Explanation:

A stack of blocks sits in equilibrium. That means, by Newton's 1st law, all blocks will remain stationary. The weight of each block is balanced by the reaction force from the block underneath it. The bottom block experiences a reaction force equals to the total weight of all blocks from the ground.

When the bottom block is removed, there will not be any reaction force from the ground. That causes a disturbance in the equilibrium. Without the balancing reaction, the blocks will have the gravity force from their weights pulling them down. By Newton 2nd law, the unbalance force will cause the blocks to accelerate towards the ground until they all crash-land.

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Suppose that a charged particle of diameter 1.00 micrometer moves with constant speed in an electric field of magnitude 1.00×105

Dovator [93]

It's a bit of a trick question, had the same one on my homework. You're given an electric field strength (1*10^5 N/C for mine), a drag force (7.25*10^-11 N) and the critical info is that it's moving with constant velocity(the particle is in equilibrium/not accelerating).
All you need is F=(K*Q1*Q2)/r^2 
Just set F=the drag force and the electric field strength is (K*Q2)/r^2, plugging those values in gives you 
(7.25*10^-11 N) = (1*10^5 N/C)*Q1 ---> Q1 = 7.25*10^-16 C

3 0

3 years ago

Read 2 more answers

What happens in the gray zone between solid and liquid?

Reil [10]

Answer:

Hence from liquid to solid or solid to liquid the transition has to cross the grey zone. This grey zone transition is is very crucial which includes the intermolecular forces acting on the molecules and each atoms which makes the change in state from hot to cold and cold to hot.

Explanation:

3 0

3 years ago

Un objeto se suelta desde determinada altura y emplea un tiempo t en caer al suelo. Si se cuadruplica la altura desde la cual se

blondinia [14]

When an object falls from a h height, you should work with the uniformly accelerated linear movement equations:

y=½*a*t²+Vo*t+yo

You should consider:

a=-g=-10m/s²

yo=h

If it’s a freefall, it means it starts from rest, which means it has no initial velocity:

Vo=0

Replacing that information in the equation:

y=½*(-10m/s²)*t²+0*t+h=-5m/s²*t²+0+h=-5m/s²*t²+h

So this is the

Besides, if you want to find out how long it takes for it to get to the floor, you should put the height of the floor as final height, which would be 0 (assuming the initial height has been measured from there):

y=0

0=-5m/s²*t²+h

5m/s²*t²=h

t²=h/(5m/s²)

t=√(h/(5m/s²))

t=√(hs²/(5m))

t=(√(h/(5m)))s

If we quadruple h:

t2=(√(h2/(5m)))s=(√(4*h1/(5m)))s=(√4)*(√h1/(5m)))s=2*(√h1/(5m)))s=2*t1

This 4 goes inside the square root, so then it converts to 2. So the new time is twice as much the previous time.

Concerning velocity, you have to use the other equation:

v=at+vo

As I said before, a is gravity and vo is zero.

v=-10m/s²*t+0=-10m/s²*t

Final velocity is directly related to time, so if time is doubled, so is velocity.

v2=-10m/s²*t2=-10m/s²*(2*t1)=2*(-10m/s²*t1)=2*v1

So the correct answer is A, and the other ones are false.

8 0

3 years ago

How do you rationalize the tension being used in Tennis Racket strings using the concept of impulse and momentum?

zheka24 [161]

Answer:

The momentum, ΔP, and therefore, kinetic energy given to the ball in a serve is the result of the product of the tension force, 'F', in the string and the time of contact, Δt, between the ball and the string

ΔP = F × Δt

Explanation:

The impulse, ΔP, is the produce of the force, 'F', applied to a body for a given period of time, Δt', that gives motion to the body, and it is equal to the change of momentum of the body

ΔP = F × Δt

The momentum, 'P', of a body is the product of the mass, 'm', of the body and its velocity, 'v'

P = m × v

Tension is the axial pulling force of a string

T = Axial Force, F $_{axial}$

The tension used in Tennis Racket strings is between 40 to 65 lbs.

When high tension is used in the string, the string is taut, and the contact duration between the Racket string and the ball is minimal, and the player needs to use more force to obtain a high momentum, and therefore, energy in the ball, which reduces control, and increase stress, as force is more emphasized

When low tension is used in the string, the Tennis Racket strings are more elastic. During a serve, the ball pushes the strings further back into the racket, such that the ball spends more time in contact with the string, (Δt is larger), and therefore, the impulse, F·Δt = ΔP, given to the ball is larger, therefore, the ball has a larger change in momentum, and therefore more energy in the intended direction.

However, a very slackened string will increase the increase area and time (large Δt) of contact of the ball and the racket such that the force given to the ball, F = ΔP/(large Δt) is reduced and therefore reduce the likelihood of gaining points from a serve against an opponent with a much forceful return of a serve.

3 0

3 years ago

How to find impulse from mass and velocity?

olga nikolaevna [1]

The momentum change =mass*velocity change. But sincevelocity change is not known another strategy must be used to find the momentum change. The strategy involves first finding the impulse (F*t = 1.0 N*s). Since impulse = momentum change, the answer is 1.0 N*s.

7 0

3 years ago