The answer is letter C. <span>A train travels from the bottom of a hill to the top of a hill, its moves slower by the time it reaches the top is an example of negative acceleration.
In physics, acceleration can be described as an objects change of velocity. When an object gains velocity, it is positive acceleration, and negative acceleration for the opposite.
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solution:
We know v0 = 0, a = 9.8, t = 4.0. We need to solve for v
so,
we use the equation:
v = v0 + at
v = 0 + 9.8*4.0
v = 39.2 m/s
Now we just need to solve for d, so we use the equation:
d = v0t + 1/2*a*t^2
d = 0*4.0 + 1/2*9.8*4.0^2
d = 78.4 m
Answer:
V= 6.974 m/s
Explanation:
Component( box) weight acting parallel and down roof 88(sin39.0°)=55.4 N
Force of kinetic friction acting parallel and up roof = 18.0 N
Fnet force acting on tool box acting parallel and down roof
Fnet= 55.4 - 18.0
Fnet=37.4 N
acceleration of tool box down roof
a = 37.4(9.81)/88.0
a= 4.169 m/s²
d = 4.90 m
t = √2d/a
t= √2(4.90)/4.169
t= 1.662 s
V = at
V= 4.169(1.662)
V= 6.974 m/s
