Answer:

Explanation:
We could use the following suvat equation:

where
s is the vertical displacement of the coin
v is its final velocity, when it hits the water
t is the time
g is the acceleration of gravity
Taking upward as positive direction, in this problem we have:
s = -1.2 m

And the coin reaches the water when
t = 1.3 s
Substituting these data, we can find v:

where the negative sign means the direction is downward.
Answer:
Option (d) is correct.
Explanation:
Work done is given by :
W = Fd, where F is force and d is displacement
Unit of work done :
The SI unit of force is Newton (N) and that of displacement is meter (m). So, the unit of work done is N-m. It is call Joule. It means that the unit of work done is Joule.
Power is given by rate at which the work is done. It is given by :
P = W/t, W is work done and t is time
Unit of power:
Unit of work is Joule (J) and that of time is second (s). It means that the unit of power is Watt and it is equal to Joule/second
Hence, the correct option is (d) "The unit for work is a joule. The unit for power is a watt, which is a joule per second".
Answer:
speed =wavelenght x frequency
v=4.5 x 10 to the -7 x 667=0.3 x 10 to the -4 m/s
speed= distance/time
time=distance/speed
t=4 x 10 to the 16/0.3 x 10 to the -4=13.33 x 10 to the 20 seconds
Explanation: