5. A body falls freely from rest. It covers as much distance in the last second of its motion as covered in the first three seconds. The body has fallen for a time of:
B) 5s
C) 7s
D) 9s
A) 35

B 5s

Explanation:

Because of the Displacement in the nth second of the free fall is 

Snth=21g(t12−t22)

Given that (tn−tn−1)=1

Displacement in 3 seconds of the free fall 

S=21gt2

S=21×10×32

S=45m

Given that: Snth=45

On solving that we get:

t1=5sec

a) cold, dry

explanation:

continental polar masses are cold and dry air masses because the cold air cannot hold much moisture. as they move into warmer air, they can trigger precipitation.

c) up is the direction the magnetic force is acting on the charge.