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3 years ago

Differences between work against friction and work against gravity.

Physics

2 answers:

Goshia [24]3 years ago

4 0

Friction is the force that is resisting the motion of an object so it will always point in the opposite direction of that of movement. ... The force of gravity points downwards . So when you do work against gravity it means that the force acting on that object points in the upward direction .

oksian1 [2.3K]3 years ago

4 0

Explanation:

<h2>hope this would be the right answer </h2>

<h2>HOPE THIS HELPS YOU.......</h2>

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Which of the following correctly describes the formula for speed?

Aleksandr [31]

Option C is the right answer

6 0

3 years ago

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What is the threshold velocity vthreshold(water) (i.e., the minimum velocity) for creating Cherenkov light from a charged partic

VladimirAG [237]

Complete Question

The complete question is shown on the first uploaded image

Answer:

$v_w = 2.256 *10^{8} \ m/s$

$v_e = 2.21 *10^{8} \ m/s$

The correct option is B

Explanation:

From the question we are told that

The refractive index of water is $n_w = 1.33$

The refractive index of ethanol is $n_e = 1.36$

Generally the threshold velocity for creating Cherenkov light from a charged particle as it travels through water is mathematically evaluated as

$v_w = \frac{c}{n_w }$

Where c is the speed of light with value $c = 3.0 *10^{8} \ m/s$

$v_w = \frac{3.0 *10^{8}}{1.33 }$

$v_w = 2.256 *10^{8} \ m/s$

Generally the threshold velocity for creating Cherenkov light from a charged particle as it travels through water is mathematically evaluated as

$v_e = \frac{ c}{n_e }$

=> $v_e = \frac{3.0 *10^{8}}{1.36 }$

=> $v_e = 2.21 *10^{8} \ m/s$

4 0

3 years ago

In the standing broad jump, one squats and then pushes off with the legs to see how far one can jump. Suppose the extension of t

muminat

<h2>⇒Answer:</h2>

In the standing broad jump, one squats and then pushes off with the legs to see how far one can jump. Suppose the extension of the legs from the crouch position is 0.600 m and the acceleration achieved from this position is 1.25 times the acceleration due to gravity, g . How far can they jump? State your assumptions. (Increased range can be achieved by swinging the arms in the direction of the jump.)

Step-by-Step Solution:

Solution 35PE

This question discusses about the increased range. So, we shall assume that the angle of jumping will be as the horizontal range is maximum at this angle.

Step 1 of 3<

/p>

The legs have an extension of 0.600 m in the crouch position.

So, m

The person is at rest initially, so the initial velocity will be zero.

The acceleration is m/s2

Acceleration m/s2

Let the final velocity be .

Step 2 of 3<

/p>

Substitute the above given values in the kinematic equation ,

m/s

Therefore, the final velocity or jumping speed is m/s

Explanation:

3 0

3 years ago

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Which four equations can be used to solve for acceleration

emmainna [20.7K]

The four equations for acceleration are obtained from the three equations of motion and from second law of motion.

Explanation:

Acceleration is defined as the rate of change of velocity with respect to time. So the change in velocity with respect to time can be determined using the three equations of motions.

So from the first equation of motion, v = u + at , we can determine the value of acceleration if time taken, final and initial velocity is known. The equation can be re-written as $a = \frac{v-u}{t}$

Similarly, from the second equation of motion, s = ut + 1/2 at², we can determine the equation for acceleration as $a = 2*\frac{s-ut}{t^{2} }$

So this is second equation for acceleration.

Then from the third equation of motion, $v^{2}- u^{2} = 2* a *s$

the acceleration equation is determined as $a = \frac{v^{2}-u^{2} }{2s}$

In addition to these three equation, another equation is present to determine the acceleration with respect to force from the Newton's second law of motion. F = Mass × acceleration. From this, acceleration = Force/mass.

So, these are the four equations for acceleration.

8 0

4 years ago

Nuclear reactors use fuel rods to heat water and generate steam. Is this process endothermic or exothermic?

Anna71 [15]

Explanation:

Exothermic reaction is defined as the reaction in which release of heat takes place. This also means that in an exothermic reaction, bond energies of reactants is less than the bond energies of products.

Hence, difference between the energies between the reactants and products releases as heat and therefore, enthalpy of the system will decrease.

Whereas in an endothermic reaction, heat is supplied from outside and absorbed by the reactant molecules. Hence, enthalpy of the system increases.

As water acts as a coolent and when fuel rods in a nuclear reactor are immersed in it then heat created by coolent is absorbed by water and then it changes into steam.

Since, absorption of heat occurs in the nuclear reactor. Therefore, it is an endothermic reaction.

Thus, we can conclude that nuclear reactors use fuel rods to heat water and generate steam. This process is endothermic.

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3 years ago

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