Answer:
v = 15.65 m/s
Explanation:
We use conservation of mechanical energy between initial (i) and final (f) states:
Pi + KEi = Pf + KEf
At the top of the cave at the instant the bat starts to fall, there is only potential energy since the bat's velocity is zero.
Pi = m g h = 600 J
and the KEi = 0 J (no velocity)
Knowing the height of the cave's roof (12.8 m) , we can find the mass of the bat:
m = 600 J / (g 12.5) = 4.9 kg
Using conservation of mechanical energy, the final state is:
Pf + KEf = 600 J
with Pf = 0 (just touching the ground)
KEf= 1/2 4.9 (v^2)
and we solve for the velocity:
600 J = 0 + 1/2 4.9 (v^2)
v^2 = 600 * 2 / 4.9 = 244.9
v = 15.65 m/s
Answer:
Incomplete third question
I think it should be
C. What was her average speed
Explanation:
Check attachment for solution
The correct answer to the question is : C) Speed is the distance an object travels within a specific unit of time, whereas acceleration is the rate at which the speed or direction of an object is changing.
EXPLANATION :
Before going to answer this question, first we have to understand speed and acceleration.
The speed of a body is defined as the rate of change of distance or the distance covered by the body per unit time. Speed is scalar quantity. Hence, it needs only magnitude for its complete specification.
The acceleration produced by a body is defined as the rate of change of velocity. We know that velocity is the speed in a particular direction. Hence, the acceleration is not only produced due to the change in magnitude of velocity as well as due to the change in direction. Hence, acceleration is a vector quantity which needs magnitude as well as direction for its complete specification.
Hence, the best difference between speed and acceleration is the third statement.
Answer:
28 J
Explanation:
Mechanical energy is the sum of kinetic and potential energy in an object that is used to do work. In other words, it is energy in an object due to its motion or position, or both.
In physics, mechanical energy (Emech) is the energy associated with the motion and position of an object usually in some force field.
Therefore:
ME = KE + PE = 25 + 3 = 28 J
