A student claims that any object in motion must experience a force that keeps it in motion. Do you agree or disagree? Explain yo
2 answers:
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Answer:
Vi = 32 [m/s]
Explanation:
In order to solve this problem we must use the following the two following kinematics equations.
The negative sign of the second term of the equation means that the velocity decreases, as indicated in the problem.
where:
Vf = final velocity = 8[m/s]
Vi = initial velocity [m/s]
a = acceleration = [m/s^2]
t = time = 5 [s]
Now replacing:
8 = Vi - 5*a
Vi = (8 + 5*a)
As we can see we have two unknowns the initial velocity and the acceleration, so we must use a second kinematics equation.
where:
d = distance = 100[m]
(8^2) = (8 + 5*a)^2 - (2*a*100)
64 = (64 + 80*a + 25*a^2) - 200*a
0 = 80*a - 200*a + 25*a^2
0 = - 120*a + 25*a^2
0 = 25*a(a - 4.8)
therefore:
a = 0 or a = 4.8 [m/s^2]
We choose the value of 4.8 as the acceleration value, since the zero value would not apply.
Returning to the first equation:
8 = Vi - (4.8*5)
Vi = 32 [m/s]
Answer:
Explanation:
The acceleration of the block can be found by the kinematics equations:
Since the plane is frictionless, the only force acting on the block along the motion of the block is its weight.
Answer:Racquet force is twice of Player force
Explanation:
Given
ball arrives at a speed of
ball returned with speed of
average Force imparted by racquet on the ball is given by
where
time of contact of ball with racquet
When it land on the player hand its final velocity becomes zero and time of contact is same as of racquet
From 1 and 2 we get
Hence the magnitude of Force by racquet is twice the Force by player