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scoundrel [369]
3 years ago
7

a stone is dropped from rest at an initial height h above the surface of the earth. Show that the speed with which it strikes th

e ground is v
Physics
1 answer:
Ksju [112]3 years ago
5 0

Answer:

v=\sqrt{2gh}

Explanation:

We could use conversation of energy. Total distance the stone will cover will be

h=\frac{1}{2} g t^{2}

the Final velocity will be

v=gt\\v=g\sqrt{\frac{2h}{g} }\\ v=\sqrt{2gh}

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Which of the following are examples of levers?
guajiro [1.7K]

The examples of levers are seesaw, door and corkscrew

Answer: Option A, B, and C

<u>Explanation:</u>

A simple machine which is capable of rotating or moving with respect to a fixed point at the center of mass is termed as lever. Lever is made up of a rigid rod which acts as the beam or the object on which the effort can be applied based on the load and a fixed hinge like thing named as fulcrum or the center of mass.

The fulcrum will be fixed and the beam will be rotating or moving with the support of fulcrum at the center for given load or effort. So among the given options, ramp is not falling under the categories of lever as door also have a fulcrum. But the ramp is only an inclined plane without fulcrum. But the Seesaw, door and the corkscrew has both fulcrum and beam which confirms them falling in the category of lever.

5 0
4 years ago
A 45kg skater and a 60kg skater are standing still, holding hands on frictionless ice. They push away from each other in opposit
frutty [35]

Answer:

The 60 kg skater is traveling at 2.63 m/s in the opposite direction from the 45 kg skater.

Explanation:

The velocity of the 60 kg skater can be found by conservation of linear momentum:

P_{i} = P_{f}

m_{a}v_{i_{a}} + m_{b}v_{i_{b}} = m_{a}v_{f_{a}} + m_{b}v_{f_{b}}  (1)

Where:

m_{a}: is the mass of the first skater = 45 kg        

m_{b}: is the mass of the second skater = 60 kg        

v_{i_{a}}: is the initial speed of the first skater = 0 (he is standing still)

v_{i_{b}}: is the initial speed of the second skater = 0 (he is standing still)

v_{f_{a}}: is the final speed of the first skater = 3.5 m/s

v_{f_{b}}: is the final speed of the second skater =?

By replacing the above values into equation (1) and solving for v_{f_{b}} we have:

0 = m_{a}v_{f_{a}} + m_{b}v_{f_{b}}

v_{f_{b}} = \frac{-m_{a}v_{f_{a}}}{m_{b}} = \frac{-45 kg*3.5 m/s}{60 kg} = -2.63 m/s

The minus sign is because the 60 kg skater is moving in the opposite direction from the other skater.

Therefore, the 60 kg skater is traveling at 2.63 m/s in the opposite direction from the 45 kg skater.

I hope it helps you!

4 0
3 years ago
Can I have some help please with any of the questions
vovangra [49]

6b: impulse is change in momentum. Change in momentum p=m[v(final)-v(initial). Final velocity is zero and initial velocity is the one you calculated before impact: -15.7 since it’s going down. Now plug in numbers and you get 78.5 in the upward direction.

6c: change in momentum p=Ft. we already calculated change in momentum. So plug it into equation and solve for t. 78.5/655= 0.119 s

Apply the same idea for question 7. Hope this helped

3 0
3 years ago
What is 60mph (miles per hour) in meters per second? ( A mile is 5280ft)<br> please someone help me
777dan777 [17]

Answer:

60mph=26.8224meters per second

Explanation:

4 0
3 years ago
You leave a 3kW heater on in your room. You put it on at 8am and leave it on until 4pm. If a unit (1kWh) costs 12.5p, how much w
natali 33 [55]

Answer:

bpc

Explanation:

8 0
3 years ago
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