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3 years ago

A boy throws a ball into the air at 10.2 m/s. Assuming that only gravity acts on the ball, how high does it rise, in m?

1 answer:

ozzi3 years ago

5 0

Answer: 5.31 meters

Explanation: Use conservation of energy. Initial energy equals final energy. Initially, there is only kinetic energy (because height = 0 initially). At the end, kinetic energy equals 0 because at max height, there is max potential energy and the ball stops moving for a split second.

mgh = .5mv^2
Masses cancel out
gh = .5v^2
(9.8)(h) = .5(10.2^2)
Solve for h. h = 5.31 meters

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Suppose you have a rock that, when it solidifies, contains 1 microgram of a radioactive isotope. How much of this isotope remain

algol13

Answer:

d) 1/32 microgram

Explanation:

First half life is the time at which the concentration of the reactant reduced to half.

Second half reaction is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/4.

Third half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/8.

Forth half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/16.

Fifth half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/32.

The initial mass of the sample = 1 microgram

After 5 half-lives, the mass should reduce to 1/32 of the original.

So the concentration left = 1/32 of 1 microgram = 1/32 microgram

7 0

3 years ago

A particle moves according to the equation x = 11t^2, where x is in meters and t is in seconds.

Savatey [412]

We are given the equation:

x = 11t^2

We use that equation to calculate for the distance traveled.
For (a)

At t=2.20 sec,
x =53.24 meters

At t=2.95 sec,
x =95.73 meters

Velocity = (95.73 meters - 53.24 meters) / (2.95 s - 2.20 s ) = 56.65 m/s

For (b)

At t=2.20 sec,
x =53.24 meters

At t=2.40 sec,
x =63.36 meters

Velocity = (63.36 meters - 53.24 meters) / (2.40 s - 2.20 s ) = 50.6 m/s

4 0

3 years ago

Please answer all of these questions and you will get the brain list

pogonyaev

Answer:

1=900j

2=140j

3=5m

Explanation:

work=force×displacement

w=450×2

w=900j

w=f×s

w=70×2

w=140j

w=f×s

200=40×s

200/40=s

s=5m

6 0

3 years ago

What is the wavelength of the wave pictured above?

love history [14]

Answer:

its counting by 4 the multi 4,8,12,16

3 0

2 years ago

If the frequency of this beam is increased while the intensity is held constant, does the number of electrons ejected per second

Ivan

Answer:

if the intensity of photons is constant then number of ejected electrons will remain same

Explanation:

As per photoelectric effect we know that when light of sufficient frequency fall on the surface of metal then electrons get ejected out of the surface with certain kinetic energy

Here the energy of photons is used to eject out the electrons from metal surface and to give the kinetic energy to the ejected electrons

so we have

$h\nu = W + KE$

here W = work function of metal which shows the energy required to eject out electrons from metal surface

KE = kinetic energy of ejected electrons

now if we increase the frequency of the photons that incident on the metal surface then in that case the incident energy will increase

So the electrons will eject out with more kinetic energy while if the number of photon is constant or the intensity of photons is constant then number of ejected electrons will remain same

8 0

3 years ago