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Paladinen [302]

3 years ago

14

. A child drops a ball from a window. The ball strikes the ground in 3.0 seconds. What is the. A child drops a ball from a windo

w. The ball strikes the ground in 3.0 seconds. What is the
velocity of the ball the instant before it hits the ground?

1 answer:

Vsevolod [243]3 years ago

3 0

Answer:

30m/s

Explanation:

Use formula for height calculation: Time = √2h/√g
From here calculate height which comes out to be: 45m(if g is taken 10)
Then use formula for velocity calculation: v = √2gh

The velocity comes out to be 30m/s

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Digiron [165]

Ep max = 6.825 J
Change of Ep = 4.425 J

3 0

3 years ago

Cart A and cart B are traveling in the same direction on a straight track. Cart A is moving at 9.25 m/s and cart B is moving at

Liula [17]

Answer:

The speed of cart B is 11.21 m/s.

Explanation:

Given that,

Speed of cart A = 9.25 m/s

Speed of cart B = 7.15 m/s

Mass of cart A = 72.0 kg

Mass of cart B = 55.0 kg

Speed of card A after collision = 6.15 m/s

We need to calculate the speed of cart B

Using conservation of momentum

$m_{A}v_{A}+m_{B}v_{B}=m_{A}v_{A}+m_{B}v_{B}$

Put the value into the formula

$72.0\times9.25+55.0\times7.15=72.0\times6.15+55.0\times v_{B}$

$v_{B}=\dfrac{72.0\times9.25+55.0\times7.15-72.0\times6.15}{55.0}$

$v_{B}=11.21\ m/s$

Hence, The speed of cart B is 11.21 m/s.

7 0

3 years ago

The electrons that are gained or lost in an ionic bond are called...?

Gala2k [10]

Answer:anion

Explanation:

4 0

3 years ago

A plane wall of thickness 0.1 mm and thermal conductivity 25 W/m K having uniform volumetric heat generation of 0.3 MW/m3 is ins

juin [17]

Answer:

The maximum temperature is 90.06° C

Explanation:

Given that

t= 0.1 mm

Heat generation

$q_g=0.3\ MW/m^3$

Heat transfer coefficient

$h=500\ W/m^2K$

Here one side(left side) of the wall is insulated so the all heat will goes in to right side .

The maximum temperature will at the left side.

Lets take maximum temperature is T

Total heat flux ,q

$q=q_g\times t$

$q=0.3\times 1000000\times 0.1 \times 10^{-3}\ W/m^2$

$q=30\ W/m^2$

So the total thermal resistance per unit area

$R=\dfrac{t}{K}+\dfrac{1}{h}$

$R=\dfrac{0.1\times 10^{-3}}{25}+\dfrac{1}{500}$

R=0.002 K/W

We know that

q=ΔT/R

30=(T-90)/0.002

T=90.06° C

The maximum temperature is 90.06° C

3 0

3 years ago

a racing car undergoes a uniform acceleration of 4.00m/s2. if the net force causing the acceleration is 3.00 times 10^3 N, what

yKpoI14uk [10]

Answer: 750Kg

Explanation:

Recall that force is the product of the mass M, of an object moving at a uniform acceleration.

i.e Force = Mass x Acceleration

In this case, Mass = ?

Force = 3.00 x 10^3 N = (3.00 x 1000N)

= 3000N

Uniform acceleration = 4.00m/s^2

Force = Mass x Acceleration

3000N = Mass x 4.00m/s^2

Mass = (3000N/4.00m/s^2)

Mass = 750Kg (The SI unit of mass is kilograms)

Thus, the mass of the car is 750Kg

4 0

3 years ago