Respuesta :
Answer:
Explanation:
Frictional force acting on the child = μ mg cosθ
, μ is coefficient of kinetic friction , m is mass of child θ is inclination
work done by frictional force
μ mg cosθ x d , d is displacement on inclined plane
work done = .13 x 276 x cos34 x 5.9
= 175.5 J
This work will be converted into heat energy.
b ) Initial energy of child = mgh + 1/2 m v ² , h is height , v is initial velocity
= 276 x 5.9 sin34 + 1/2 x 276 / 9.8 x .518² [ mass m = 276 / g ]
= 910.59 + 3.77
= 914.36 J
loss of energy due to friction = 175.5
Net energy at the bottom
= 738.86 J
If v be the velocity at the bottom
1/2 m v² = 738 .86
.5 x (276 / 9.8) x v² = 738.86
v² = 52.47
v = 7.24 m /s .
Answer:
Explanation:
weight of child, mg = 276 N
distance, s = 5.90 m
angle of inclination, θ = 34°
coefficient of kinetic friction, μk = 0.130
(a)
The work done by the friction force is converted into heat.
W = μk x mg x Cos θ x s
W = 0.130 x 276 x Cos 34° x 5.90
W = 175.5 Joule
Thus, the amount of thermal energy is 175.5 Joule.
(b)
initial speed, u = 0.518 m/s
Let the speed at the bottom is v.
let the acceleration is a.
a = g Sinθ - μk g Cosθ
a = 9.8 (Sin 34 - 0.130 x Cos 34)
a = 9.8 (0.559 - 0.108)
a = 4.42 m/s
Use III equation of motion
v² = u² + 2 a s
v² = 0.518 x 0.518 + 2 x 4.42 x 5.9
v² = 0.2683 + 52.156
v = 7.24 m/s
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