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2 years ago

6

What evidence is there that work is being done?

1 answer:

suter [353]2 years ago

4 0

Answer:

The boy uses force to move the rock a distance.

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A ball is thrown horizontally from a 20-m-high building with a speed of 5.0m/s

KATRIN_1 [288]

1) Horizontal velocity, Vx

Vx is constant and equal to 5.0 m/s

The graph Vx(t) = 5.0 m/s is a horizontal line (parallel to the horizontal t-axis). that intercepts the vertical-axis at 5.0 and runs from t = 0 to t = 2.

2) Vertical velocity, Vy

Vy = gt = 10t

d = at^2 / 2 => tmax = √(2d / a) = √(2*20m/10m/s^2) = 2 s

Graph Vy is an inclined line with slope 10 m/s^2, that runs from t =0 to t = 2 s, and passes through the points (0,0), (1,10), and (2,20).

3 0

3 years ago

Which letter explains why no machine is 100 percent efficient.

kondaur [170]

Answer:

A

Explanation:

Think about rubbing your hands together- the friciton produces heat

4 0

2 years ago

What is the frequency of an X-ray with wavelength 0.13 nm ? Assume that the wave travels in free space. Express your answer to t

dem82 [27]

Answer:

Frequency, $f=2.30\times 10^{18}\ Hz$

Explanation:

Given that,

The wavelength of the x-rays, $\lambda=0.13\ nm=0.13\times 10^{-9}\ m$

We need to find the frequency of an x-ray. All electromagnetic wave travel with a speed of light. It is given by the formula as :

$c=f\lambda$

f is the frequency

$f=\dfrac{c}{\lambda}\\\\f=\dfrac{3\times 10^8}{0.13\times 10^{-9}}\\\\f=2.30\times 10^{18}\ Hz$

So, the frequency of an x-ray is $2.30\times 10^{18}\ Hz$ . Hence, this is the required solution.

5 0

3 years ago

A car traveling at a speed of 13 meters per second accelerates uniformly to a speed of 25 meters per second in 5.0 seconds. 11-

Aleks04 [339]

Answer:

$a=2.4\ m/s^2$

Explanation:

Given that,

Initial speed of a car, u = 13 m/s

Final speed of a car, v = 25 m/s

Time, t = 5 s

We need to find the acceleration of the car during this 5.0 second time interval. Let a is the acceleration. It can be calculated as :

$a=\dfrac{v-u}{t}\\\\a=\dfrac{25-13}{5}\\\\=2.4\ m/s^2$

So, the acceleration of the car is $2.4\ m/s^2$ .

7 0

3 years ago

You can carry a 50 N weight up a flight of stairs that is 3 m high in 10 s. Then you carry 40 N up two flights of stairs in 20 s

d1i1m1o1n [39]

You can do 50 and 10 and carry the 30 and it would be in the same power so you’ll have the same energy

5 0

3 years ago