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2 years ago

If a force always acts perpendicular to an object's direction of motion, that force cannot change the object's kinetic energy.

1 answer:

5 0

This is very good conceptual question and can clear your doubts regarding work-energy theorem.
Whenever force is perpendicular to the direction of the motion, work done by that force is zero.
According to work-energy theorem,
Work done by all the force = change in kinetic energy.

here, work done = 0.
Therefore,
0=change in kinetic energy
This means kinetic energy remains constant.
Hope this helps

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Jupiter is 317 times more massive than the Earth. An astronaut on Jupiter would _____. weigh less than on Earth weigh more than

Softa [21]

Since "you will weigh more on jupiter" isn't an option, your answer is B."weigh more than on Earth" btw ik this is a late answer but for the people out there still searching for an answer hope this helps!

8 0

2 years ago

A 91.5 kg football player running east at 2.73 m/s tackles a 63.5 kg player running east at 3.09 m/s. what is their velocity aft

Ierofanga [76]

2.88 m/s is the velocity afterward.

Explanation:

By using the law of conservation of momentum

Initial momentum = final momentum

$\mathrm{m}_{1} \mathrm{u}_{1}+\mathrm{m}_{2} \mathrm{u}_{2}=\left(\mathrm{m}_{1}+\mathrm{m}_{2}\right) \times \mathrm{v} \text { equation }(1)$

$\mathrm{m}_{1}=91.5 \mathrm{kg} \text { is the mass of the first player }\mathrm{m}_{2}=63.5 \mathrm{kg}$

$\mathrm{m}_{2}=63.5 \mathrm{kg} \text { is the mass of the second player }$

$\mathrm{u}_{1}=2.73 \mathrm{m} / \mathrm{s} \text { is the initial velocity of the first player (choosing east as positive direction) }$

$\mathrm{u}_{2}=3.09 \mathrm{m} / \mathrm{s} \text { is the initial velocity of the second player }$

v = is their combined velocity afterwards

Solving equation (1) for v

$V=\frac{m_{1} u_{2}+m_{2} u_{2}}{m_{1}+m_{2}}$

$\mathrm{V}=\frac{(91.5 \times 2.73)+(63.5 \times 3.09)}{91.5+63.5}$

$\mathrm{V}=\frac{(249.7+196.2)}{155}$

$\mathrm{V}=\frac{445.9}{155}$

V = 2.88 m/s

Therefore the velocity afterward is 2.88 m/s.

7 0

2 years ago

Paula is studying two different animals. Both animals are classified within the same genus, but they are different species. Base

Ksivusya [100]

Answer:c

Explanation:

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6 0

2 years ago

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A skier is moving down a snowy hill with an acceleration of 0.40 m/s2. The angle of the slope is 5.0∘ to the horizontal. What is

kirill115 [55]

Answer:

1.25377 m/s²

Explanation:

m = Mass of person

g = Acceleration due to gravity = 9.81 m/s²

$\mu$ = Coefficient of friction

$\theta$ = Slope

From Newton's second law

$mgsin\theta-f=ma\\\Rightarrow mgsin\theta-\mu mgcos\theta=ma\\\Rightarrow \mu=\frac{gsin\theta-a}{gcos\theta}\\\Rightarrow \mu=\frac{9.81\times sin5-0.4}{9.81\times cos5}\\\Rightarrow \mu=0.04655$

Applying $\mu$ to the above equation and $\theta=10^{\circ}$

$mgsin\theta-\mu mgcos\theta=ma\\\Rightarrow a=gsin\theta-\mu gcos\theta\\\Rightarrow a=9.81\times sin10-0.04655\times 9.81\times cos10\\\Rightarrow a=1.25377\ m/s^2$

The acceleration of the same skier when she is moving down a hill is 1.25377 m/s²

3 0

2 years ago

Two planets having equal masses are in circular orbit around a star. Planet A has a smaller orbital radius than planet B. Which

vova2212 [387]

Answer:

Explanation:

To solve this, we must know two things.

First, the force of gravity acting on an orbiting object is equal to its mass times centripetal acceleration.

Second, the force of gravity between two objects is defined by Newton's law of universal gravitation: Fg = mMG/r², where Fg is the force of gravity, m and M are the masses of the objects, G is the universal constant of gravitation, and r is the distance between the objects.

Therefore:

Fg = m v²/r

mMG/r² = m v²/r

v² = MG/r

The potential energy of each planet is:

PE = mgr = m (MG/r²) r = mMG/r

The kinetic energy of each planet is:

KE = 1/2 mv² = 1/2 m (MG/r) = 1/2 mMG/r

The total mechanical energy is:

ME = PE + KE = 3/2 mMG/r

Since both planets have the same mass, the only difference is the orbital radius. Since planet A has a smaller orbital radius, it has more potential energy, more kinetic energy, and more mechanical energy.

6 0

2 years ago