A student drops a rubber ball onto a surface. Assume that this is a closed system. The ball bounces, but each successive bounce
is shorter than the one before it. Eventually, the ball comes to a stop. Which statement provides evidence that supports the idea that energy is conserved in this closed system?
A. The ball moves through air, suggesting that the ball has mechanical energy.
B. The ball needs a push or pull to start moving, suggesting it needs a constant input of energy.
C. The ball makes a sound with each bounce, suggesting that some kinetic energy transformed into sound.
D. The ball bounces many times, suggesting the energy is used up efficiently
A. The ball moves through air, suggesting that the ball has mechanical energy.
B. The ball needs a push or pull to start moving, suggesting it needs a constant input of energy.
C. The ball makes a sound with each bounce, suggesting that some kinetic energy transformed into sound.
D. The ball bounces many times, suggesting the energy is used up efficiently
2 answers:
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Answer:
a) 25.5°(south of east)
b) 119 s
c) 238 m
Explanation:
solution:
we have river speed =2 m/s
velocity of motorboat relative to water is =4.2 m/s
so speed will be:
a) =
+
solving graphically
=4.7 m/s
Ф=
=25.5°(south of east)
b) time to cross the river: t==
=119 s
c) d==(2)(119)=238 m
note :
pic is attached
Answer:
5308.34 N/C
Explanation:
Given:
Surface density of each plate (σ) = 47.0 nC/m² =
Separation between the plates (d) = 2.20 cm
We know, from Gauss law for a thin sheet of plate that, the electric field at a point near the sheet of surface density 'σ' is given as:
Now, as the plates are oppositely charged, so the electric field in the region between the plates will be in same direction and thus their magnitudes gets added up. Therefore,
Now, plug in for 'σ' and
for
and solve for the electric field. This gives,
Therefore, the electric field between the plates has a magnitude of 5308.34 N/C
Answer:
0 J
Explanation:
From the diagram below; we would notice that the Force (F) = Tension (T)
Also the angle θ adjacent to the perpendicular line = 90 °
The Workdone W = F. d
W = Fd cos θ
W = Fd cos 90°
W = Fd (0)
W = 0 J
Hence the force is perpendicular to the direction of displacement and the net work done in a circular motion in one complete revolution is = 0
