ans: B
Kinetic energy = 
= 
= 50J
ps. the height will only affect its potential energy, not kinetic.
Let the tension in the thread will be at angle theta
now by force balance in x and y directions we can say



now for the height of the kite we can use



<em>so it will be at height 32.23 m from ground</em>
Answer:
PART A)
External force will be 75 N
PART B)
distance moved will be 1.125 m
Explanation:
PART A)
Given that net force on the mower is

now we also know that friction force due to ground is given as

now we have



so external force will be 75 N
PART B)
deceleration due to friction when external force is removed from it


now we can find the distance by kinematics



so the distance moved will be 1.125 m
Answer:
a. Wavelength = λ = 20 cm
b. Next distance of maximum intensity will be 40 cm
Explanation:
a. The distance between the two speakers is 20cm. SInce the intensity is maximum which refers that we have constructive interference and the phase difference must be an even multiple of π and equivalent path difference is nλ.
Now when distance increases upto 30 cm between the speakers, the sound intensity becomes zero which means that there is destructive interference and equivalent path is now increased from nλ to nλ + λ/2.
This we get the equation:
(nλ + λ/2) - nλ = 30-20
λ/2 = 10
λ = 20 cm
b. at what distance, sound intensity will be maximum again.
For next point calculation for maximum sound intensity, the path difference must be increased (n+1) λ. The distance must increase by λ/2 from the point of zero intensity.
= 30 + λ/2
= 30 + 20/2
=30+10
=40 cm