If a lens is submerged in water, what happens to its focal length?
A) It decreases.
B) It stays the same.
C) It becomes negative.
D) It increases.
Question 2
A boy kicks a football from ground level with a certain initial velocity at an angle 30.0 above the horizontal. In 2.00 seconds the ball completes its trajectory and hits the ground. What is the initial velocity of the ball?
A) 9.80 m/s
B) 4.90 m/s
C) 39.2 m/s
D) 19.6 m/s
E) 78.4 m/s