Answer:(a)10 ft/s
(b)4 ft/s
Explanation:
Given
height of light 
height of man
From diagram
differentiate both sides
Tip of shadow is moving at the rate of
(b)rate at which length of his shadow is changing
Length of shadow is 
differentiating w.r.t time
Answer: current I = 0.5 A
Explanation:
Given that the
Potential difference V = 10V
Resistance R = 20 ohms
According to ohms law
V = IR
Where
V = potential difference
I = current
R = resistance
Make I the subject of formula
I = V/R
I = 10/20
I = 0.5 Ampere
Answer with Explanation:
We are given that
Fundamental frequency,f=88.4 Hz
Speed of sound,v=343 m/s
We have to find the first three overtones.
Tube is closed
The overtone of closed pipe is equal to odd number of fundamental frequency.
Therefore, the overtone of tuba
Where n=3,5,7,..
Substitute n=3
For second overtone
For third overtone
Most likely it would dislodge the coconut on the way down due to gravity because on the way up the gravity would slow down the rock but on they down the gravity pulls the rock
Answer: work = 1,305kJ
Explanation:
angle= 30°
force= 1,500N
distance= 1,000m
The formula for work is : Work= force x distance, however there is an angle of 30° between the direction of force applied and the direction of motion, therefore force must be decomposed to its value on the horizontal axis which is the direction of motion by using the cosine of the very angle.
W= F×cos(α)×D
W= 1,500×cos (30)×1,000
W= 1,305kJ ( kilojoules)
