Yesterday was the day that we got canceled on it so we had a lot
The crate would slide forward
Answer:
Yes
Explanation:
There was a force, 500 lb.
and a motion in the direction of the force, in this case a negative direction.
Therefore the lifter did negative work on the mass of the barbell against gravity.
Gravity would do positive work against the mass of weight when the lifter lowers the barbell as the force vector and the motion vector are in the same direction.
Answer:
a)P= -4800 i
b)F= 0
Explanation:
Given that
r = (4570-160 t) i + 2930 j + 130 k
We know that velocity is rate of change of the space vector.
V= dr/dt
r = (4570-160 t) i + 2930 j + 130 k
dr/dt= -160 i + 0 + 0
dr/dt= -160 i
V= -160 i
It means that velocity is in only x-direction
We also know that acceleration is the rate of change of velocity .
a= dV/dt
V= -160 i
dV/dt=0
So we can say that acceleration is zero.
a= 0
From Second law of Newton'
Force = Mass x acceleration
F= 300 x 0
F= 0
We know that linear momentum P
P = m V
Given that m= 300 kg
P = 300 x (-160 i)
P= -4800 i
