Answer:
7 meters, 2.8 meters
Explanation:
work done (nm) = force (n) * distance (m)
140= 20 * m
140/20 = m
m=7 meters
140= 50 * m
140/50 = m
m= 2.8 meters
Answer:
The maximum safe depth in salt water is 3758.2 m.
Explanation:
Given that,
Diameter = 20 cm
Radius = 10 cm
Thickness = 9.0 cm
Force 
Inside pressure = 1.0 atm
We need to calculate the area
Using formula of area

Put the value into the formula


We need to calculate the pressure
Using formula of pressure

Put the value into the formula



We need to calculate the maximum depth
Using equation of pressure


Put the value into the formula


Hence, The maximum safe depth in salt water is 3758.2 m.
Explanation:
Given that,
Object-to-image distance d= 71 cm
Image distance = 26 cm
We need to calculate the object distance


We need to calculate the focal length
Using formula of lens

put the value into the formula



The focal length of the lens is 35.52.
(B). Given that,
Object distance = 95 cm
Focal length = 29 cm
We need to calculate the distance of the image
Using formula of lens

Put the value in to the formula




We need to calculate the magnification
Using formula of magnification



The magnification is 0.233.
The image is virtual.
Hence, This is the required solution.
Answer:
Option C, increases and decreases
Explanation:
When an object making noise approaches you, the wave frequency increases leading to a higher pitch. Conversely, when it moves away from you or retreats, the wave frequency decreases leading to a lower pitch. This can be observed in ambulance sirens.
Answer:
0.78333 m/s in the opposite direction
1.566 m/s in the same direction
Explanation:
= Mass of penny = 0.0025 kg
= Mass of nickel = 0.005 kg
= Initial Velocity of penny = 2.35 m/s
= Initial Velocity of nickel = 0 m/s
= Final Velocity of penny
= Final Velocity of nickel
As momentum and Energy is conserved


From the two equations we get

The final velocity of the penny is 0.78333 m/s in the opposite direction

The final velocity of the nickel is 1.566 m/s in the same direction