Since power = work done/time, 60= work done/120, work done = 120*60 = 7200. So,work done = 7200N (Newton).
I'm not sure if you're supposed to convert the seconds to time.
To solve any problem in math or physics, you collect all the formulas,
laws, rules, and equations that you know about the subject, then, along
with the given information, use them to find the missing information.
So the answer to "how" really depends on what information you're given.
When an object is moving with uniform circular motion, the centripetal acceleration of the object d. is directed toward the center of motion.
Answer:
P=6.25N and Q=16.25N
Explanation:
In order to solve this problem we must first draw a free body diagram for both situation, (see attached picture).
Now, we need to analyze the two free body diagrams. So let's analyze the first diagram. Since the body is accelerated, then the sum of forces is equal to mass times acceleration, so we get:
We can assume there will be only the two mentioned forces P and Q, so
the sum of forces will be:
P+Q=ma
P+Q=22.5N
We can do the same analysis for the second free body diagram:
Q-P=10.5N
so now we have a system of equations we can solve by elimination:
Q+P=22.5N
Q-P=10.5N
Now, we can add the two equations together so the P force is eliminated, so we get:
2Q=32.5N
now we can solve for Q:
so
Q=16.25N
Now we can use any of the equations to find P.
Q+P=22.5N
P=22.5N-Q
when substituting for Q we get:
P=22.5N-16.25N
so
P=6.25N
Answer:
a ) 2.68 m / s
b ) 1.47 m
Explanation:
The jumper will go down with acceleration as long as net force on it becomes zero . Net force of (mg - kx ) will act on it where kx is the restoring force acting in upward direction.
At the time of equilibrium
mg - kx = 0
x = mg / k
= (60 x 9.8 ) / 800
= 0.735 m
At this moment , let its velocity be equal to V
Applying conservation of energy
kinetic energy of jumper + elastic energy of cord = loss of potential energy of the jumper
1/2 m V² + 1/2 k x² = mg x
.5 x 60 x V² + .5 x 800 x .735 x .735 = 60 x 9.8 x .735
30 V² + 216.09 = 432.18
V = 2.68 m / s
b ) At lowest point , kinetic energy is zero and loss of potential energy will be equal to stored elastic energy.
1/2 k x² = mgx
x = 2 m g / k
= (2 x 60 x 9.8) / 800
= 1.47 m
