The average acceleration is the ratio of which of the following quantities?

How long does it take light to travel 850 km in a vacuum? Answer in ms.(Express your answer to two significant figures.)

poizon [28]

Answer:

0.002833 sec

Explanation:

Speed of light in vacuum is $3\times 10^{8}m/sec$

Given distance = 850 km = 850×1000=850000 m

We have to calculate the time that light take to travel the distance 850 km

Time $T=\frac{distance }{speed}=\frac{850000}{3\times 10^8}=2.833\times 10^{-3}sec$

So the time taken by light to travel 850 km is 0.002833 sec

5 0

3 years ago

Which is true regarding the penetrating power of radiation? (2 points) Select one:

Monica [59]

Answer:d

Explanation:

Alpha particles are heaviest among alpha, beta and gamma so they have least amount of Penetration compared to both.

Gamma Particles are lightest among three so they can Penetrate most .

The order of Penetration is given by

Alpha< Beta < Gamma

3 0

2 years ago

An austrain who lived in vienna who composed graetest music for waltz dance<br>

Stolb23 [73]

Johann Strauss II

hope this helps

6 0

2 years ago

A diver can change his rotational inertia by drawing his arms andlegs close to his body in the tuck position. After he leaves th

NeX [460]

Answer:

3.14946 rad/s

Explanation:

$I_i$ = Intial moment of inertia

$I_f$ = Final moment of inertia

$\omega_i$ = Initial angular velocity

$\omega_f$ = Final angular velocity = $\dfrac{2}{1.33}\times 2\pi\ rad/s$

$\dfrac{I_f}{I_i}=\dfrac{1}{3}$

In this system the angular momentum is conserved

$L_i=L_f\\\Rightarrow I_i\omega_i=I_f\omega_f\\\Rightarrow \omega_i=\dfrac{I_f\omega_f}{I_i}\\\Rightarrow \omega_i=\dfrac{1\times \dfrac{2}{1.33}\times 2\pi}{3}\\\Rightarrow \omega_i=3.14946\ rad/s$

The angular velocity when the diver left the board is 3.14946 rad/s

3 0

2 years ago

Sort these statements about machines based on whether they are correct or incorrect.

insens350 [35]

as well.

1. Correct

Explanation

An inclined plane is a flat surface which lie at an angle, Its one end is higher than the other this inclined plane is used as an aid for raising or lowering a load. Staircase also work in similar manner

2. Correct

Explanation

yes all simple machine have a fulcrum

3. Incorrect

Explanation

when we swim that time our arms and legs 'push' the water due to which water displaced in backward direction so her we applied a positive work on the water. According to Newton's Third Law,same magnitude of work is done by water in opposite direction to push us back on our arms and legs. therefore water also does positive work on us.

4. incorrect

Explanation

The force exerted by a machine on an object is input force

5. Incorrect

Explanation

when the input force is greater than the output force that time machine have mechanical advantage of less than 1.

8 0

2 years ago

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