Increase .... decrease .... presumably it's the "best shape" for a body which has been formed by the gravitational force
Answer:
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Answer:
A) 199.78 J
B) 9.292x10^14 J
C) 4.2x10^7 m/s
D) 0.65 m
E) 1.13x10^-8 sec
D) 2.94x10^-9 sec
Explanation:
mass of ball = 0.0580 kg
A)
If smashed at v = 83.0 m/s, KE is
KE = 0.5mv^2
= 0.5 x 0.0580 x 83.0^2
= 199.78 J
B) if returned at v = 1.79×10^8 m/s, KE will be
KE = 0.5mv^2
= 0.5 x 0.0580 x (1.79×10^8)^2
= 9.292x10^14 J
C) during Einstein's return, velocity of rabbit relative to players is
Vr = 2.21×108 m/s
Rabbit's velocity relative to ball = 2.21×10^8 - 1.79×10^8
= 4.2x10^7 m/s
D) the rabbit's speed approaches the speed of light so we consider relativistic effect. The rabbit's measured distance is
l = l°( 1 - v^2/c^2)
= 2.5(1 - 2.21/3)
= 2.5 x 0.26
= 0.65 m
E) according to the players, the time taken by the rabbit is
t = d/v = 2.5/ 2.21×10^8
= 1.13x10^-8 sec
F) the time for rabbit as measured by rabbit is relativistic
t = t°( 1 - v^2/c^2)
= 1.13x10^-8 (1 - 2.21/3)
= 1.13x10^-8 x 0.26
= 2.94x10^-9 sec
Answer:
159 N
Explanation:
The force of friction, Fr is a product of coefficient of feiction and the normal force. Therefore, Fr=uN where N is the normal force and u is coefficient of friction. Here, we have two coefficients of friction but since it is sliding, then we use coefficient of kinetic energy. Substituting 0.25 for u and 636 N for N then
Fr=0.25*636=159 N
Therefore, the force of friction is equivalent to 159 N
