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3 years ago

How much force does it take to accelerate a 2,000-kg car at 4 m/s

Physics

1 answer:

Leona [35]3 years ago

3 0

Answer:

C. 8,000 N

Explanation:

Newton's second law of motion describes the relationship between an object's mass and the amount of force needed to accelerate it.

This law can be expresses as F=ma,

where

F - force acting on an object
m- the mass of an object
a - its acceleration

The more mass an object has, the more force you need to accelerate it. And the greater the force, the greater the object's acceleration.

F = ma

=2000×4 = 8,000 N

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Which of the following represents an upright image? A. -do B. +m C. -m D. +do

Tom [10]

Answer:

B. +m

Explanation:

The magnification of an image is defined as the ratio between the size of the image and of the object:

$m = \frac{y'}{y}$

where we have

y' = size of the image

y = size of the object

There are two possible situations:

- When m is positive, y' has same sign as y: this means that the image image is upright

- When m is negative, y' has opposite sign to y: this means that the image is upside down

Therefore, the correct option representing an upright image is

B. +m

5 0

3 years ago

A 25kg chair initially at rest on a horizontal floor requires a 165 N horizontal force to set it in motion. Once the chair is in

SCORPION-xisa [38]

Answer:

$\mu_k=0.51$

Explanation:

Given that

Mass , m = 25 kg

We know that when body is in rest condition then static friction force act on the body and when body is in motion the kinetic friction force act on the body .That is why these two forces are given as follows

Static friction force ,fs= 165 N

Kinetic friction force ,fk = 127 N

If the body is moving with constant velocity ,it means that acceleration of that body is zero and all the forces are balanced.

Lets take coefficient of kinetic friction = μk

The kinetic friction is given as follows

fk = μk m g

Now by putting the values

127 = μk x 25 x 9.81

$\mu_k=\dfrac{127}{25\times 9.81}$

$\mu_k=0.51$

Therefore the value of coefficient of kinetic friction will be 0.51

4 0

3 years ago

Why does the evaporation of sweat cool down your skin?

Ne4ueva [31]

So sweat helps cool you down two ways. First, it makes your skin feel cooler when it's wet. And when it evaporates it removes some heat. But sweat will only evaporatoin an environment where there isn't much water in the air.

6 0

3 years ago

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Explanation: One can pick up a nail using the curved part of the horseshoe magnet farthest from the poles. A horse shoe magnet h

PIT_PIT [208]

Answer:

is there anymore choices than A

4 0

2 years ago

There is a 250-m-high cliff at half dome in yosemite national park in california. suppose a boulder breaks loose from the top of

lorasvet [3.4K]

Part A. For this part, we use two equations for linear motion:

y = y0 + v0 t + 0.5 g t^2 ---> 1

vf = v0 + g t ---> 2

First we solve for t using equation 1: y0 = 0 (initial point at top), y = 250 m, v0 = 0 (at rest)

250 = 0.5 (9.8) t^2

t = 7.143 s

Now we solve for final velocity vf using equation 2:

vf = g t

vf = 9.8 (7.143)

vf = 70 m/s

Part B. First we solve for the time it takes for the sound to reach the tourist.

t(sound) = 250 / 335 = 0.746 s

Therefore the total time would be:

t = 0.746 s + 0.300 s

t = 1.05 s

Hence there is enough time for the tourist to get out before the boulder hits him.

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3 years ago

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