Answer:
time rising = 34 / 9.8 = 3.47 sec
total time in air = 2 * 3.47 sec = 6.94 sec
(time rising must equal time falling)
R = 17 m/s * 6.94 s = 118 m
Can also use range formula
R = v^2 sin (2 theta) / g
tan theta = 34 / 17 = 2
theta = 63.4 deg
2 theta = 126.9 deg
sin 126.9 = .8
v^2 = 17^2 + 34^2 = 1445 m^2/s^2
R = 1445 * .8 / 9.8 = 118 m agreeing with answer found above
If the sign of work is negative, that means the force and the motion are in opposite directions.
Let's say you see something roll off of the shelf. You catch it, and you let it down slowly and gently.
Gravity exerted down-force on it and it moved down. Gravity did positive work on it.
YOU exerted UP-force on it and it moved down. YOU did negative work on it.
(Also, the falling object exerted down-force on your hand, and your hand moved down. The falling object did positive work on your hand ! Where did THAT energy come from ? It came from the potential energy that the object had while it was on the shelf. Your hand absorbed that energy on the way down, doing negative work. So the object didn't have any kinetic energy when it reached the floor, and it did NOT splinter the floor or shatter in smithereens. It had barely enough energy left to make a sound when it hit the floor.)
Answer:
tensional force
Explanation:
It usually exist in fluid or any liquid substance where by an object is put before it
e.g An ant can walk on water without submersed in it.
Answer:
The force exerted by the biceps is 143.8 kgf.
Explanation:
To calculate the force exerted by the biceps, we calculate the momentum in the elbow.
This momentum has to be zero so that her forearm remains motionless.
Being:
W: mass weight (6.15 kg)
d_W= distance to the mass weight (0.425 m)
A: weight of the forearm (2.25 kg)
d_A: distance to the center of mass of the forearm (0.425/2=0.2125 m)
H: force exerted by the biceps
d_H: distance to the point of connection of the biceps (0.0215 m)
The momemtum is:
The force exerted by the biceps is 143.8 kgf.
