Answer:
0.13
Explanation:
Draw a free body diagram. There are three forces:
Weight force mg pulling down.
Normal force N pushing perpendicular to the incline.
Friction force Nμ pushing parallel up the incline.
Sum of the forces perpendicular to the incline:
∑F = ma
N − mg cos θ = 0
N = mg cos θ
Sum of the forces parallel down the incline:
∑F = ma
mg sin θ − Nμ = ma
mg sin θ − mgμ cos θ = ma
g sin θ − gμ cos θ = a
gμ cos θ = g sin θ − a
μ = (g sin θ − a) / (g cos θ)
Given a = 3.3 m/s² and θ = 27°:
μ = (9.8 m/s² sin 27° − 3.3 m/s²) / (9.8 m/s² cos 27°)
μ = 0.13
Answer:
1.53 s
Explanation:
Initially vertical component of velocity of the ball, uy = 7.5 m/s
Net displacement is vertical direction is zero, Δy =0
Use second equation of motion:
Δy = uy t + 0.5 a t²
Here, acceleration a = -g (g =9.8 m/s²)
Substitute all the values and solve for g
0 = 7.5 t -0.5 (9.8)t²
7.5 t = 4.9 t²
t = 1.53 s
The formula for the acceleration due to gravity is:
a = Gm/r²
where
G is the universal gravitational constant = 6.6726 x 10⁻¹¹ N-m²/kg²
m is the mass of planet
r is the radius of planet
So, if they have the same a:
m₁/r₁² = m₂/r₂²
So, if m₁ = m and r₂ = 2r₁,
m/r₁² = m₂/(2r₁)²
m₂ = 4m
<em>Thus, the answer is D.</em>
Even though all materials are at the same temperature when they come out of the dryer, some like the zipper are far better conductors of heat and can burn you. Cloth is not a good conductor of heat.
Answer:
the act of emitting radiation spontaneously
Explanation:
