Answer:
225 N
Explanation:
"Below the horizontal" means he's pushing down at an angle.
Draw a free body diagram of the box. There are three forces: normal force N pushing up, weight force mg pulling down, and the applied force F at an angle θ.
Sum of forces in the y direction:
∑F = ma
N − mg − F sin θ = 0
N = F sin θ + mg
Plug in values:
N = (50 N) (sin 30°) + (20.0 kg) (10 m/s²)
N = 225 N
Answer:
Starts on Saturday, June 1
and ends on
Saturday, November 30
Explanation:
Answer:
2v
Explanation:
The function of the velocity is:
v = v0 + a.t, where v is the top speed, v0 is the initial speed, a is the acceleration and t the time.
Both the tortoise and the hare start at rest, so v0 = 0. For the tortoise:
v = a.t
For the hare:
v' = a't', but a' = a and t' = 2t
v' = a*2t
v' = 2*at
v' = 2v
Answer:
The expression for the magnitude of the accelerations is
Explanation:
According the Newton´s second law:
Clearing T for second equation:
T = ma + mg
Replacing in the first equation:
Mg - ma - mg = Ma
Ma + ma = Mg - mg
a(M + m) = g(M - m)
A fiber-optic cable is made up of incredibly thin strands of glass or plastic known as optical fibers; one cable can have as few as two strands or as many as several hundred. Light travels down a fiber-optic cable by bouncing repeatedly off the walls. If<span> light hits glass at a really shallow angle (less than 42 degrees), it reflects back in again—as though the glass were really a </span>mirror<span>. This phenomenon is called </span>total internal reflection<span>. It's one of the things that keeps light inside the pipe.</span>