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9 months ago

4

a cricket ball is hit so that it travels straight up in the air and it require 3 second to reach the maximum height its initial

velocity is

1 answer:

Lisa [10]9 months ago

0 0

Answer:

v = u - gt

At maximum heitht, v = 0

0 = u - (9.8)(3)

u = 29.4 m/s initial velocity

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A charge 2Q is located at the origin while a second charge –Q is located at x = a. Where should a third charge be placed so that

bulgar [2K]

Answer:

If the third charge is placed at a distance $b=\sqrt{a^{2} +2ab}$ the net force on the charge will be zero

Explanation:

Consider the diagram below.

Let us add a new charge Q at a distance b from the origin.

Let the force that the charge 2Q exert on the new charge (Q) be

$F1 = \frac{k2Q^{2} }{(a+b)^{2} }$

Let the force that charge -Q exerts on the new charge be

$F2= \frac{-kQ^{2} }{b^{2} }$

For the third charge in equilibrium,

$\\F1 + F2 = 0\\\\\frac{k2Q^{2} }{(a+b)^{2} } - \frac{kQ^{2} }{(b)^{2} } =0$

Solving this will give us a quadratic equation which will be further simplified.

$\frac{k2Qx^{2}b ^{2}-kQ^{2}(a+b)^{2} }{(a+b)^{2}b^{2} }=0\\k2Qx^{2}b ^{2}-kQ^{2}(a+b)^{2} = 0\\\\kQx^{2}(2b ^{2}-(a+b)^{2}) = 0\\((2b ^{2}-(a+b)^{2}) = 0\\\\(2b ^{2}-a^{2}-2ab-b^{2}=0\\b^{2}-a^{2} -2ab=0\\a^{2} -b^{2} + 2ab =0\\\\\\$

Making b the subject of the formula, we can get the distance that the third charge will be placed .

$b=\sqrt{a^{2} +2ab}$

So if the third charge is placed at a distance $b=\sqrt{a^{2} +2ab}$ the net force on the charge will be zero

if real values were plugged in, it will be easier for us to determine the value of b

7 0

7 months ago

During a game the same batter swings at a ball thrown by the pitcher and hits a line drive. Just before the ball is hit it is tr

sergeinik [125]

Answer:

The total work on the ball is 36.25 Joules

Explanation:

There is an important principle on classical mechanics that is the work-energy principle it states that the total work on an object is equal the change on its kinetic energy, mathematically expressed as:

$W_{net}=\Delta K = K_f -K_i$ (1)

With W net the total work, Kf the final kinetic energy and Ki the initial kinetic energy. We're going to use this principle to calculate the total work on the baseball by the force exerted by the bat.

Kinetic energy is the energy related with the movement of an object and every classical object with velocity has some kinetic energy, it is defined as:

$K=\frac{mv^2}{2}$

With m the mass of the object and v its velocity, knowing this we can use on:

$W_{net}= \frac{mv_f^2 -mv_i^2}{2}=\frac{m(v_f^2 -v_i^2)}{2}$

In our case vf is the velocity just after the hit and vi the velocity just before the hit. For an average baseball its mass is 145g that is 0.145 kg, then

$W_{net}=\frac{0.145*(30.0^2 -20.0^2)}{2}$

$W_{net}=36.25 J$

8 0

1 year ago

Give examples of at least three critical questions of society that science can help answer.

baherus [9]

Answer:

Explanation:

Reasons for a high/low rate of Mortality: Science can be very invaluable determining the high/low rate of mortality in an area by conducting extensive research on various factors the people (of a society) are exposed to that causes the rate of mortality. In the case of high-rate of mortality, science can assist in providing guidelines in reducing the rate.

Epidemiology and Treatment of diseases: If there is a rise in the number of people affected by a particular disease in a society, science can help provide answers by determining if indeed the diseases are the same or just appear the same. Science can also assist in preventing and providing cure (treatment) to this disease.

Optimization and improved nutritive diet: Science assists in optimizing food products in order to get maximum benefits from the food eaten. A society might have some food substances that are not well stored or processed before eating; which could lead to loss of important nutrients, science can help correct this societal norm through research.

8 0

9 months ago

A student pushes on a 20.0 kg box with a force of 50 N at an angle of 30° below the horizontal. The box accelerates at a rate of

PtichkaEL [24]

Answer:

225 N

Explanation:

"Below the horizontal" means he's pushing down at an angle.

Draw a free body diagram of the box. There are three forces: normal force N pushing up, weight force mg pulling down, and the applied force F at an angle θ.

Sum of forces in the y direction:

∑F = ma

N − mg − F sin θ = 0

N = F sin θ + mg

Plug in values:

N = (50 N) (sin 30°) + (20.0 kg) (10 m/s²)

N = 225 N

8 0

11 months ago

A bathtub contains 65 gallons of water and the total weight of the tub and water is approximately 931.925 pounds. You pull the p

levacccp [35]

Answer:

$Q = 8,345 * v$

Explanation:

So, we are looking for an expression of the amount of water that has been drained from the tub. The expression is in terms of v that represent the number of gallons of water drained since the plug was pulled. Since we are interested in the pounds of water that has been drained from the tub we need to take into account that for every gallon of water drained, 8.345 pounds have left the tub. Therefore, the expression for the weight of water Q that has been drained from the tub in terms of v is simply :

$Q = 8,345 * v$

Where v is the amount of gallons that has been drained from the tub.

Have a nice day. let me know if I can help with anything else

8 0

1 year ago