You throw a ball into a box and close the lid. You hear the ball bouncing around inside as the ball’s energy changes from gravit
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1) Physical principles:
a) Total mechanical energy = kinetic energy + potential energy.
b) Total mechanical energy is conserved (neglecting external forces, like drag and friction)
2) Notation:
a) Total mechanical energy: ME.
b) Kinetic energy: KE
c) Gravitational potential energy: PE
∴ ME = KE + PE = constant
3) Solution:
a) Since, ME is conserved, it is constant and would be represented in the graph by a horizontal line.
b) At start (t = 0), the ball has only KE, so KE =ME = E and PE = 0
c) As the time goes, the ball gains altitude (PE increases) and loses speed (KE decreases).
d) PE increases from 0 to a maximum value. In the graph that happens at t = 2s.
At that point, KE = 0, and PE = ME.
That is the point of highest altitude and where the speed is zero.
d) From t = 2 seg, the ball starts to lose altitude, then the ball loses PE, and gains KE.
Just before reaching the ground, at t = 4s, the ball has the same initial KE and PE as at t = 0: KE = ME and PE = 0.
The PE may be sketched on the same graph along with the KE and the ME.
The graph is attached. The red line is the ME and the blue line is the PE.
Note that at any point in the graph PE + KE = ME.
Answer:
Final velocity will be 7.31 m/sec
Explanation:
We have given applied force F = 150 N
Mass of the object m = 11 KG
Distance traveled by the object s = 2.5 m
Coefficient of kinetic friction
Acceleration due to gravity
So frictional force applied on the object
So net force = 150-32.34 = 117.66 N
As work done us equal to
So work done =
Now according to work energy theorem work done is equal to change in kinetic energy
So
v =7.31 m/sec
So velocity final velocity will be 7.31 m/sec