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4 years ago

5

Calculate the speed of a bike rider who accelerates (from rest) for 5 seconds down a hill at an acceleration of 8

1 answer:

olya-2409 [2.1K]4 years ago

6 0

Answer:

speed=abs(v)=40ms^-1

Explanation:

acceleration, a = (v-u)/t

since initial velocity u=0 (at rest) and a=8ms^-2,

8=v/5

hence after 5 seconds, v=40ms^-1

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Yuliya22 [10]

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3 years ago

Read 2 more answers

What is an atom? Give three 3 examples.

Assoli18 [71]

Answer:

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Hope this helps....

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8 0

3 years ago

The engine in an imaginary sports car can provide constant power to the wheels over a range of speeds from 0 to 70 miles per hou

kirill115 [55]

Answer:

Part A

it would take 6 sec

it would take 3 sec

Explanation:

We are told that the power supplied to the wheel is constant which means that the sport car is gaining energy i.e

$power \ \alpha \ energy$

Hence if power is constantly supplied energy constantly increase

From the formula of the Kinetic energy

$KE = \frac{1}{2} mv^2$

we can see that as the speed doubles from 29 mph to 58 mph the energy needed is $2^2$ = 4 times of the energy from the formula

Also the time needed would also be 4 times because energy i directly proportional to time

Hence to reach 58mph the time that it would take is

= $4* 1.5sec = 6sec$

We are told that the ground pushes the car with a constant force and

F = ma

this means that the acceleration is also constant

now from newtons law

v = u +at

Looking at it we see that final velocity is directly proportional with time

hence it would take twice the time to reach twice the final velocity

Time to reach 58mph = 3 s

since time to reach 29 mph( $\frac{1}{2} \ of \ [58mph]$ ) =( $\frac{1}{2} \ of \ 3sec$ )1.5 s

6 0

3 years ago

An ideal gas Carnot cycle with air in a piston cylinder has a high temperature of 1200 K and a heat rejection at 400 K. During t

lana [24]

Answer:

The specific heat capacity is q_{L}=126.12kJ/kg

The efficiency of the temperature is n_{TH}=0.67

Explanation:

The p-v diagram illustration is in the attachment

T_{H} means high temperature

T_{L} means low temperature

The energy equation :

$q_{h}$ = R* $T_{h}$ in( $V_{2}$ / $V_{1}$ )

$=0.287 * 1200 ln(3)$

$=0.287*1318.33$

$=378.36kJ/kg$

The specific heat capacity:

$q_{L}$ =q_{h}*(T_{L}/T_{H})

q_{L}=378.36 * (400/1200)

q_{L}=378.36 * 0.333

q_{L}=126.12kJ/kg

The efficiency of the temperature will be:

$n_{TH}$ =1 - ( $T_{L}$ / $T_{H}$ )

n_{TH}=1-(400/1200)

n_{TH}=1-0.333

n_{TH}=0.67

4 0

3 years ago

Name the property of bodies to resist a change in their velocity.

brilliants [131]

Answer:

inertia

Explanation:

it's newton's first law

3 0

3 years ago