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masha68 [24]
3 years ago
7

What is the answer to this question?

Physics
1 answer:
icang [17]3 years ago
8 0

Answer:

Explanation:

In a velocity/time (aka acceleration) graph, the slope of a line indicates the value of the acceleration in m/s/s. Acceleration is the change in velocity over the change in time. From 0 - 2 seconds, there is no change in velocity, so the acceleration during this interval is 0 (which is the same as the slope of the line). From 2 - 4 seconds, the slope of the line is -2, so the acceleration during the time interval from 2 to 4 seconds is -2 (negative because David is slowing down but is still going the same direction: to the right).

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In each cycle, a heat engine an input of 1940 J of heat and exhausts 1480 J of heat. What is the thermal efficiency?
AleksAgata [21]

Answer:

0.237 (23.7 %)

Explanation:

The thermal efficiency of an engine is given by:

\eta=\frac{W}{Q_{in}}

where

W is the useful work output of the engine

Q_{in} is the heat in input

Here we have:

Q_{in}=1940 J

and the work done is the total heat in input minus the heat exhausted:

W=1940 J - 1480 J=460 J

So, the efficiency is

\eta=\frac{460 J}{1940 J}=0.237 (23.7 %)

8 0
3 years ago
If a 50-kg Person is running at a rate of 2m/s, the person's momentum is _____ kg• m/s.
sergiy2304 [10]

Answer:

100

Explanation:

Use equation p=mv

p=(50kg)(2m/s)= 100

8 0
3 years ago
A person jogs eight complete laps around a quarter-mile track in a total time of 13.1 minutes
ExtremeBDS [4]
Speed and velocity have the same magnitudes. The only difference is that speed is a scalar quantity and velocity is a vector quantity. In other words, speed is just a magnitude, while velocity is a magnitude with direction. They're essentially the same.

Let's convert miles to meters and minutes to seconds

1/4 mile = 402.34 meters ( 1 mile = 1609 m)
13.1 minutes = 786 seconds (1 minute = 60 seconds)

Speed is calculated as distance over time, thus,

Speed = (402.34 meters)*8/786 seconds
a.) Speed = 4.1 m./s
b.) Velocity = 4.1 m/s

5 0
3 years ago
An airplane accelerates from rest down a runway at 3.20 m/s2 for 32.8 seconds until it lifts off the ground. Determine the dista
vagabundo [1.1K]

Answer:

s=1721.344m  ,v=104.96m/s.

Explanation:

using thr equation of motion;

s=ut+\frac{1}{2}at^{2}

u=0, plane starts from rest,

s=\frac{1}{2}at^{2}

a=3.2m/s^{2}, t=32.8s \\ s=\frac{1}{2}*3.2*32.8^{2}

s=1721.344m

v=u+at

v=0 +3.2*32.8

v=104.96m/s

8 0
3 years ago
At a given time of​ day, the ratio of the height of an object to the length of its shadow is the same for all objects. If a 4​-f
katrin2010 [14]

Answer:35.2 ft

Explanation:

Given

height of stick =4 ft

shadow length =2.8 ft

Angle of elevation of sun is

tan\theta =\frac{4}{2.8}

let the height of tree be h

as \thetawill remain same thus

tan\theta =\frac{h}{24.64}

\frac{4}{2.8}=\frac{h}{24.64}

h=35.2 ft

8 0
4 years ago
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