Respuesta :
Explanation:
(a) Formula to calculate the force of kinetic friction is as follows.
f = [tex]\mu N[/tex]
= [tex]\mu mg Cos (\theta)[/tex]
Putting the given values into the above formula as follows.
f = [tex]\mu mg Cos (\theta)[/tex]
= [tex]0.118 \times 57.4 kg \times 9.8 \times Cos (28.1^{o})[/tex]
= [tex]0.118 \times 57.4 kg \times 9.8 \times 0.882[/tex]
= 58.54 N
Hence, the force of kinetic friction is 58.54 N.
(b) Net force experienced by the block will be as follows.
F = [tex]mg Sin (\theta) - f[/tex]
ma = [tex]mg Sin (\theta) - \mu mg Cos (\theta)[/tex]
or, a = [tex]g[Sin (\theta) - \mu Cos (\theta)][/tex]
= [tex]9.8[Sin(28.1) - Cos(28.1)][/tex]
= [tex]9.8 \times (0.471 - 0.882)[/tex]
= 4.03 [tex]m/s^{2}[/tex]
Therefore, the acceleration is 4.03 [tex]m/s^{2}[/tex].
(c) According to the third equation of motion,
[tex]v^{2} = u^{2} + 2as[/tex]
= [tex]0 + 2 \times 4.03 \times 17.2[/tex]
= 138.63 m/s
Hence, the speed she is traveling when she reaches the bottom of the slide is 138.63 m/s.
Answer:
Explanation:
mass, m = 57.4 kg
distance, d = 17.2 m
angle of inclination, θ = 28.1°
initial velocity, u = 0 m/s
coefficient of kinetic friction, μk = 0.108
(a) N is the normal reaction acting on the student.
N = mg Cosθ
N = 57.4 x 9.8 x Cos 28.1
N = 496.2 N
Friction force = μk x N
Friction force = 0.108 x 496.2 = 53.6 N
Let a is the acceleration
ma = mg Sinθ - friction force
ma = 57.4 x 9.8 x Sin 28.1 - 53.6
a = 3.7 m/s²
Let the speed is v.
v² = u² + 2ad
v² = 0 + 2 x 3.7 x 17.2
v = 11.3 m/s
