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3 years ago

In which situation is no work considered to be done by a force?

Physics

1 answer:

Ber [7]3 years ago

7 0

Answer:

O B. when the angle between the force and displacement is 90°

Explanation:

<h3>work defined as $w = f cos Ф * d$ . </h3><h3>work can only be done if object moves(displacement) in the direction of force. now a quick one. if you since the varrious angles into the cosine, you would see that Cos 90 will give zero which implies that no work is done. Again, angle means it is perpendicular and so it is not in the direction of force.</h3>

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An automobile with 0.500 m radius tires travels 80,000 km before wearing them out. How many revolutions do the tires make, negle

Zinaida [17]

Answer:

n = 25,464,790.89 revolutions

The tires have made 25,464,790.89 revolutions

Explanation:

Given;

Radius of tires r = 0.5 m

Total distance travelled d = 80,000 km = 80,000,000 m

1 revolution = 2πr

Total distance d = number of revolutions n × 2πr

d = n×2πr

d = 2πnr

Making n the subject of formula;

n = d/2πr

Substituting the given values;

n = (80,000,000)/(2×π×0.5)

n = 25,464,790.89470 revolutions

n = 25,464,790.89 revolutions

The tires have made 25,464,790.89 revolutions

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3 years ago

A crew team rows a boat at a rate of 20 km/h in still water. In practice on a river, the team rows for 30 minutes up the river (

sweet-ann [11.9K]

In the second 30 mins, the speed should be 20 + 1.5 = 21.5 km/h

So S = 21.5 * 30/60 = 10.75 km

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3 years ago

A child with a mass of 23 kg rides a bike with a mass of 5.5 kg at a velocity of 4.5 m/s to the south. Compare the momentum of t

serg [7]

Answer:

Explanation:

Given the following data;

Mass of child = 23 kg

Mass of bike = 5.5 kg

Velocity = 4.5 m/s

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

$Momentum = mass * velocity$

To find the momentum of each of them;

I. Momentum of the child

Momentum C = mass * velocity

Momentum C = 23 * 4.5

Momentum C = 103.5 Kgm/s

II. Momentum of the bike

Momentum B = mass * velocity

Momentum B = 5.5 * 4.5

Momentum B = 24.75 Kgm/s

Hence, we can deduce from the calculations that the momentum of the child is greater than that of the bike because of the higher mass possessed by the child.

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3 years ago

Why does pressure change with elevation and depth?

nasty-shy [4]

<span>the deeper you go the more pressure...that's for depth</span>

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3 years ago

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What type of matter is absorbent

Elanso [62]

Gas, liquid, or solid

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3 years ago