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2 years ago

What is the acceleration of a dog that runs from 3 m/s to 6 m/s over a distance of 90m?

Physics

1 answer:

KonstantinChe [14]2 years ago

6 0

Answer:

solution given:

acceleration (a)=?

initial velocity (u)=3m/s

final velocity (v)=6m/s

distance (s)=90m

we have

v²=u²+2as

substituting value

6²=3²+2*a*90

36=9+180a

36-9=180a

a=25/180

<u>a=0.1388m/s²</u>

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a steam engine work on its vicinity 285 k heat is released with the help of 225 c energy absorbed to the system what is the effi

-Dominant- [34]

The efficiency of the steam engine is 78.9% because the rest of the work input is used to overcome friction.

<h3>What is efficiency of machines?</h3>

Efficiency of a machine expresses the useful work done by a a machine as a percentage.

Efficiency of a machine = work output/work input × 100 %%

The efficiency of machines are always less than 100% percent due to energy losses due to friction and heat.

For the steam engine:

Work output = 225 J

Work input = 285 J

Efficiency = 225/285 × 100% = 78.9 %

Therefore, the efficiency of the steam engine is 78.9% because the rest of the work input is used to overcome friction.

Learn more about efficiency of machines at: brainly.com/question/7536036

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6 0

1 year ago

A Yugo can accelerate from rest to a speed of 28 m/s in 20 s. What is the average acceleration of the car? What distance does it

harina [27]

Answer:

Explanation:

a=28/20

a=1.4 m/s²

V²=v0²+2a.D

28²=0+2x1.4D

784 = 2.8D

D = 280 m

6 0

2 years ago

Sally Leadfoot was pulled over on her way from Syracuse to Ithaca by an officer claiming she was speeding. The speed limit is 65

Citrus2011 [14]

Sally's average speed is <u>35.3 mi/h.</u>

Average speed of a body is the total distance traveled in the given time interval.

Express the distance d traveled in miles.

$d=\frac{97 km}{1.6 km/m\\i} \\ = 60 mi$

Express the time t traveled in hours.

$t =\frac{102 min}{60 min/hr}\\ = 1.7 h$

Calculate the average speed v.

$v =\frac{d}{t} \\ =\frac{60 mi}{1.7h} \\ = 35.3 mi/h$

Her average speed is 35.3 mi/h, which is less than the speed limit of 65 mi/h.

However, the average speed of an object is different from its instantaneous speed. It could be possible that at the time when the officer apprehended her, Sally could have been travelling at a speed greater than the prescribed speed limit, which would have prompted the officer to issue a speeding ticket to her.

Thus, the average speed of a person cannot be considered as a bench mark for speeding offences, since her instantaneous speed could have been higher than the speeding limit and yet she could have had an average speed less than the speeding limit.

3 0

3 years ago

A 50 kg pitcher throws a baseball with a mass of 0.15 kg. If the ball is thrown with a positive velocity of 35 m/s and there is

Andreas93 [3]

The velocity of the pitcher is <u>0.105 m/s</u> in a direction opposite to the velocity of the ball.

When no external force acts on a system, the total momentum of the system is conserved. The total initial momentum of the system is equal to the total final momentum of the system.

The pitcher and the ball are initially at rest, therefore, the total initial momentum of the system is zero.

Since no external forces act on the system comprising of pitcher and the ball, the total final momentum of the system is also equal to zero.

If the mass of the pitcher is mp and its speed is vp, the mass of the ball is mb and the ball's speed is vb, then the final momentum of the system of pitcher and the ball is given by,

$p=m_pv_p+m_bv_b=0$