Answer:
The work done to get you safely away from the test is 2.47 X 10⁴ J.
Explanation:
Given;
length of the rope, L = 70 ft
mass per unit length of the rope, μ = 2 lb/ft
your mass, W = 120 lbs
mass of the 70 ft rope = 2 lb/ft x 70 ft
= 140 lbs.
Total mass to be pulled to the helicopter, M = 120 lbs + 140 lbs
= 260 lbs
The work done is calculated from work-energy theorem as follows;
W = Mgh
where;
g is acceleration due gravity = 32.17 ft/s²
h is height the total mass is raised = length of the rope = 70 ft
W = 260 Lb x 32.17 ft/s² x 70 ft
W = 585494 lb.ft²/s²
1 lb.ft²/s² = 0.0421 J
W = 585494 lb.ft²/s² = 2.47 X 10⁴ J.
Therefore, the work done to get you safely away from the test is 2.47 X 10⁴ J.
Answer:
1.87 s
Explanation:
d = distance traveled by the water wave = 64 m
t = time taken to travel the distance = 14 s
= speed of water wave
Speed of water wave is given as
= 4.6 m/s
= wavelength of the wave = 859 cm = 8.59 m
T = period of the wave
period of the wave is given as
T = 1.87 s
Answer: The option (C) is correct. The energy travels horizontally.
Explanation: When the pebble is thrown into a calm lake, there will be disturbance in the lake. The ripples are formed from the center and move outward because the energy is carried out from particle to particle.
The distribution of the energy among the particles starts from center and it will carry out outward. This disturbance will occur horizontally.
Therefore, the energy travels horizontally.
Answer:
pushes it forward, pushes it backwards and then it moves