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Serggg [28]
3 years ago
12

A rock is dropped from the top of a tall building. How high is the building if it takes 3.25seconds for the rock to strike the g

round? Ignore the effects of air resistance. A) 169m B)15.9m C)51.8m D) 32.2m
Physics
1 answer:
romanna [79]3 years ago
5 0

Answer:

C)51.8m

Explanation:

Kinematics equation:

y=v_{oy}*t+1/2*g*t^2

in this case:

v_{oy}=0

y=1/2*9.81*3.25^2=51.8m

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You are on the roof of the physics building, 46.0 above the ground . Your physics professor, who is 1.80 tall, is walking alongs
Fudgin [204]

Answer:

3.6m

Explanation:

if you are at a building that is 46m above the ground, and the professor is 1.80m, the egg must fall:

46m - 1.80m = 44.2m

the egg must fall for 44.2m to land on the head of the professor.

Now, how many time this takes?

we have to use the following free fall equation:

h=v_{0}t+\frac{1}{2}gt^2

where h is the height, v_{0} is the initial velocity, in this case v_{0}=0. g is the acceleration of gravity: g=9.81m/s and t is time, thus:

h=\frac{1}{2}gt^2

clearing for time:

2h=gt^2\\\frac{2h}{g}=t^2\\\sqrt{\frac{2h}{g}} =t

we know that the egg has to fall for 44.2m, so h=44.2, and g=9.81m/s, so we the time is:

t=\sqrt{\frac{2(44.2m)}{9.8m/s^2} }=\sqrt{\frac{88.4m}{9.81m/s^2} } =\sqrt{9.011s^2}= 3.002s

Finally, if the professor has a speed of v=1.2m/s, it has to be at a distance:

d=vt

and t=3.002s:

d=(1.2m/s)(3.002s)=3.6m

so the answer is the professor has to be 3.6m far from the building when you release the egg

7 0
3 years ago
What was the only option for getting the Apollo 13 astronauts back to Earth alive?
Vera_Pavlovna [14]
They got back in the Lunar Explorer Module
4 0
3 years ago
Read 2 more answers
A horizontal force of 100 N is used to pull a crate, which weighs 500 N, at constant velocity across a horizontal floor. What is
Ilya [14]

Answer:

0.2

Explanation:

Horizontal force=100N

Weight of crate=500 N

We have to find the coefficient of kinetic friction.

Normal ,N=Weight=500N

Horizontal force,F_x=\mu_kN

Where F_x=Horizontal force

N=Normal force

\mu_k=Coefficient of kinetic friction

Substitute the values in the formula

100=\mu_k(500)

\mu_k=\frac{100}{500}=0.2

Hence, the coefficient of kinetic friction =0.2

8 0
3 years ago
How does climate change affect the ocean??
Debora [2.8K]
It raises the water level because of the melting glaciers. 
6 0
4 years ago
A 90-meter train travels at a constant speed of 10 meters per second. How long will it take to cross a 0.06 bridge?
salantis [7]

Answer:

The time taken for the train to cross the bridge is 9.01 s

Explanation:

Given;

length of the train, L₁ = 90 m

length of the bridge, L₂ = 0.06 m

speed of the train, v = 10 m/s

Total distance to be traveled, = L₁ + L₂

                                                  = 90 m + 0.06 m

                                                   = 90.06 m

Time of motion = Distance / speed

Time of motion = 90.06 / 10

Time of motion = 9.006 s ≅ 9.01 s

Therefore, the time taken for the train to cross the bridge is 9.01 s

5 0
3 years ago
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