Google it and I bet you find the correct answer
Threshhold frequency is defined as the minimum light frequency necessary to start photo-electric emission from the surface. This frequency is just effecient enough to emit electrons without any additional force or energy. this minimum frequency creates the necessary result that is sought by the person. The photo electric emission for certain metals can occir with threshhold frequency. The importance of this threshhold frequency lies in the fact that this has been used to create numerous instruments like amplifiers for use of people.
Its acceleration will change
plane is flying at an altitude of 70 m
now if an object is dropped from it then time taken by object to drop on ground will be given as

here initial speed in vertical direction must be zero as plane is moving horizontal
given that
y = 70 m
a = 9.8 m/s^2


now since the plane is moving horizontally with speed v = 44 m/s
so the horizontal distance moved by the object will be



so the distance moved by the box is 166.3 m
Answer:
Mass of the disk will be 2.976 kg
Explanation:
We have given force F = 45 N
Radius of the disk r = 0.12 m
Angular acceleration 
We know that torque 
And 
So
, here I is moment of inertia
So 

We know that moment of inertia 
So 
m = 2.976 kg