A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
Answer:
5 m/s
Explanation:
Given that,
A vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west.
It is assumed to find the resultant velocity of the vehicle. Let east side is positive and west is negative. So,

Hence, the resultant velocity of the vehicle is equal to 5 m/s.
It would be static friction which is what you have to overcome when an object is not in motion. When you move an object friction works against it like gravity and air resistance. I hope this helps!