A rock is dropped from a 200 m high cliff. How long does it take to fall (a) the first 100 m and (b) the last 50 m?
The basic equation you want is:
s=at22
Solving for t:
t=2sa−−−√
We’ll assume a=9.8 , so 2a−−√=14.9−−−√≈0.4518
So, for (a)s=100 , so t=0.4518100−−−√=4.518
The total time is 0.4518200−−−√≈6.389
The time to fall 150 m is 0.4518150−−−√≈5.533
So the time to fall the last 50 m is 6.389 - 5.533 = 0.856 seconds
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Answer:
option d) -9 J
Explanation:
Given:
Mass, m = 3.0 kg
time, t = 6.0 seconds
Velocity of mass, v = 2.0 m/s
height, h = 2 m
Now, using the concept of work-Energy theorem
we have
Net work done = change in kinetic energy
or
Work done by gravity + work done by the friction = Final kinetic energy - Initial kinetic energy
mgh +
= 
on substituting the values in the above equation, we get
3 × 9.8 × 2 +
= 
or
58.8 +
= 6
or
= -52.8 J
here negative sign depicts that the work is done against the motion of the mass
also,
Power = (Work done)/time
or
Power = -52.8/6 = -8.8 W ≈ 9 J
Hence, option d) -9 J is correct
Answer:
option B...
they represent different concept...
i hope this will answer your question
Answer:
soccer
Explanation:
soccer can inprove your health because you use all parts of your body playing it. You use your legs because you are running and you use your arms for doing throw ins. Soccer is also good for you because you are not playing for too long. Usually one soccer game is only 1 hour.
Hope this helps
Answer:
The value is 
Explanation:
From the question we are told that
The velocity which the rover is suppose to land with is
The mass of the rover and the parachute is
The drag coefficient is
The atmospheric density of Earth is 
The acceleration due to gravity in Mars is 
Generally the Mars atmosphere density is mathematically represented as

=> 
=> 
Generally the drag force on the rover and the parachute is mathematically represented as

=>
=>
Gnerally this drag force is mathematically represented as

Here A is the frontal area
So

=> 
=> 