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LuckyWell [14K]

3 years ago

5

An object of mass 0.5 kg is swung in uniform circular motion. The radius is 2 meters, and the force exerted is 4 N. Calculate th

e magnitude of the velocity.

1 answer:

Katarina [22]3 years ago

8 0

Using
F= mv²/r
4 = 0.5×v² / 2
8 /0.5 = v²
v²=16
v= √16
v= 4 ms-¹

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Assume that a 15-kg ball moving at 8 m/s strikes a wall perpendicularly and rebounds elastically at the same speed. What is the

Aleks [24]

I think u should follow the formulae F=MA. So I think the answer is 120N

5 0

2 years ago

In the Daytona 500 auto race, a Ford Thunderbird and a Mercedes Benz are moving side by side down a straightaway at 71.0 m/s. Th

elena55 [62]

<u>Answer:</u>

<em>Thunderbird is 995.157 meters behind the Mercedes</em>

<u>Explanation:</u>

It is given that all the cars were moving at a speed of 71 m/s when the driver of Thunderbird decided to take a pit stop and slows down for 250 m. She spent 5 seconds in the pit stop.

Here final velocity $v=0 \ m/s$

initial velocity $u= 71 m/s$ distance

Distance covered in the slowing down phase = $250 m$

$v^2-u^2=2as$

$a= \frac {(v^2-u^2)}{2s}$

$a = \frac {(0^2-71^2)}{(2 \times 250)}=-10.082 \ m/s^2$

$v=u+at$

$t= \frac {(v-u)}{a}$

$= \frac {(0-71)}{(-10.082)}=7.042 s$

$t_1=7.042 s$

The car is in the pit stop for 5s $t_2=5 s$

After restart it accelerates for 350 m to reach the earlier velocity 71 m/s

$a= \frac {(v^2-u^2)}{(2\times s)} = \frac{(71^2-0^2)}{(2 \times 370)} =6.81 \ m/s^2$

$v=u+at$

$t= \frac{(v-u)}{a}$

$t= \frac{(71-0)}{6.81}= 10.425 s$

$t_3=10.425 s$

total time= $t_1 +t_2+t_3=7.042+5+10.425=22.467 s$

Distance covered by the Mercedes Benz during this time is given by $s=vt=71 \times 22.467= 1595.157 m$

Distance covered by the Thunderbird during this time= $250+350=600 m$

Difference between distance covered by the Mercedes and Thunderbird

= $1595.157-600=995.157 m$

Thus the Mercedes is 995.157 m ahead of the Thunderbird.

6 0

3 years ago

Which of the following is an example of a physical change but not a chemical change?

vazorg [7]

A water pipe freezes and cracks on a cold night. <em> (D)</em>

There are three physical changes going on in this scenario:

1). The air gets cold and dark at night.

2). The water in the pipe freezes and expands.

3). The pipe cracks.

There are no chemical changes in the description.

7 0

3 years ago

Read 2 more answers

Which describes why nonrenewable energy resources are used more frequently than renewable ones?

Helga [31]

The correct answer is C They are inexpensive to use. Trust me I just took the test.

Mark me Brainiest please.

6 0

3 years ago

Read 2 more answers

Your bedroom has a rectangular shape and you want to measure its size. You use a tape that is precise to 0.001 mm and find that

avanturin [10]

This question is in two parts. This is not the correct multiple choice options for this part a.

The second part had the option

b)If your bedroom has a circular shape, and its diameter measured 6.32 , which of the following numbers would be the most precise value for its area?

a)30 m^2

b) 31.4 m^2

c)31.37 m^2

d)31.371 m^2

Answer:

A. 17.0 m²

B. 31.4 m²

Explanation:

The formula for the calculation of the area of a rectangle is given as

Area = length x width

The length = 3.547 m

The width = 4.79 m

Then area = 3.547 x 4.79

= 16.990m²

When approximated = 17.0m²

This is the most precise measurement for the area of the bedroom.

B.

We solve b using this formula

Area = pi(diameter/2)^2

= 3.14(6.32/2)²

= 3.14 x 9.9856

= 31.4 m²

4 0

2 years ago