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2 years ago

What average force is necessary to bring a 50.2-kg sled from rest to a speed of 2.8 m/s in a period of 20.1 s?

1 answer:

7 0

To solve this problem we will use the concepts related to the Impulse-Momentum Theorem for which it is specified as the product between force and change in time

$\Delta p = F\Delta t$

And

\Delta p = m\Delta v

Where,

$F = Force$

$\Delta t = \text{Change in Time}$

$\Delta v = \text{Change in velocity}$

$m = mass$

Rearranging to find the Force we have that

$F = \frac{\Delta p}{\Delta t}$

Using the expression between mass and velocity

$F = \frac{m(v_f-v_i)}{\Delta t}$

Our values are given as,

$m = 50.2kg\\v_i = 0m/s \\v_f = 2.8m/s \\\Delta t = 20.1s$

Then replacing we have that

$F = 6.99N$

Therefore the average force is 6.99N

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On the way to school, the bus speeds up from 20 m/s to 36 m/s in 4 seconds. What distance

Tresset [83]

Answer B. 112 m

Step-by-Step Explanation

initial velocity u = 20 m /s
final velocity v = 36 m /s
time taken t = 4 s
acceleration = (v - U) / t
= (36 - 20) / 4
a=4m/s2
from the formula
7-u2=2as , sis distance covered
putting the values
362-202=2×4×s
1296 - 400 = 8 x S
S= 112 m

4 0

1 year ago

A 90 kg man stands in a very strong wind moving at 17 m/s at torso height. As you know, he will need to lean in to the wind, and

victus00 [196]

Answer:

a) $t=195.948N.m$

b) $\phi=13.6 \textdegree$

Explanation:

From the question we are told that:

Density $\rho=1.225kg/m^2$

Velocity of wind $v=14m/s$

Dimension of rectangle:50 cm wide and 90 cm

Drag coefficient $\mu=2.05$

Generally the equation for Force is mathematically given by

$F=\frac{1}{2}\muA\rhov^2$

$F=\frac{1}{2}2.05(50*90*\frac{1}{10000})*1.225*17^2$

$F=163.29$

Therefore Torque

$t=F*r*sin\theta$

$t=163.29*1.2*sin90$

$t=195.948N.m$

Generally the equation for torque due to weight is mathematically given by

$t=d*Mg*sin90$

Where

$d=sin \phi$

Therefore

$t=sin \phi*Mg*sin90$

$195.948=833sin \phi$

$\phi=sin^{-1}\frac{195.948}{833}$

$\phi=13.6 \textdegree$

5 0

2 years ago

Problems with solar energy include _____.

german

First choice: the inability of current technology to capture
large amounts of the Sun's energy

Well, it's true that large amounts of it get away ... our 'efficiency' at capturing it is still rather low. But the amount of free energy we're able to capture is still huge and significant, so this isn't really a major problem.

Second choice: the inability of current technology to store
captured solar energy

No. We're pretty good at building batteries to store small amounts, or raising water to store large amounts. Storage could be better and cheaper than it is, but we can store huge amounts of captured solar energy right now, so this isn't a major problem either.

Third choice: inconsistencies in the availability of the resource

I think this is it. If we come to depend on solar energy, then we're
expectedly out of luck at night, and we may unexpectedly be out
of luck during long periods of overcast skies.

Fourth choice: lack of demand for solar energy

If there is a lack of demand, it's purely a result of willful manipulation
of the market by those whose interests are hurt by solar energy.

4 0

2 years ago

Read 2 more answers

1. The process of producing energy by utilizing heat trapped inside the earth's

babymother [125]

Answer:

Explanation:

The process is called Geo-Thermal energy because it's an inexhaustible source of energy

6 0

2 years ago

Read 2 more answers

During a baseball game, a batter hits a high pop-up. If the ball remains in the air for 4.02 s, how high above the point where i

alukav5142 [94]

Answer:

d = 19.796m

Explanation:

Since the ball is in the air for 4.02 seconds, the ball should reach the maximum point from the ground in half the total time, therefore, t=2.01s to reach maximum height. At the maximum height, the velocity in the y-direction is 0.

So we know t=2.01, vi=0, g=a=9.8m/s and we are solving for d.

Next, you look for a kinematic equation that has these parameters and the one you should choose is:

$d=vt+\frac{1}{2}at^2$

Now by substituting values in, we get

$d=(0\frac{m}{s})*(2.01s)+\frac{1}{2}(9.8\frac{m}{s^2})(2.01)^2$

d = 19.796m

7 0

2 years ago