Answer:
zero
Explanation:
Consider two identical wave pulses on a rope having a fixed end. Suppose the first pulse reaches the end of the rope, is reflected back, and then meets the second pulse, both waves will be out of phase by π radians. Therefore, they form destructive interference and hence the amplitude of the resultant pulse would be zero.
The only vertical forces are weight and normal force, and they balance since the surface is horizontal. The horizontal forces are the applied force (uppercase F) in the direction the block slides and the frictional force (lowercase f) in the opposite direction.
Apply Newton's 2nd Law in the horizontal direction:
ΣF = ma
F - f = ma
where f = µmg
F - µmg = ma
F = m(a +µg)
F = (20 kg)(1.4 m/s² + 0.28(9.8 m/s²)
F = 83 N
Answer:
196J
Explanation:
Given parameters:
Mass of skateboard = 1kg
Height off the ground = 20m
Unknown:
Potential energy = ?
Solution:
The potential energy is the energy due to the position of a body above the ground.
It is mathematically expressed as:
Potential energy = mass x acceleration due gravity x height
Potential energy = 1 x 9.8 x 20 = 196J
The only colours that are in the spectrum are red, orange, yellow, green, blue, indigo and violet. hope this helps!
