1) Acceleration: 
The motion of the plane is a uniformly accelerated motion, so we can find its acceleration by using the suvat equation

where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
Here we have
v = 150 m/s is the final velocity of the plane
u = 0 (it starts from rest)
a=?
s = 1500 m is the displacement
Solving for a, we find

2. Time: 20 s
For this part of the problem, we can use another suvat equation:

v is the final velocity
u is the initial velocity
a is the acceleration
t is the time
Here we already know:
v = 150 m/s is the final velocity of the plane
u = 0 (it starts from rest)
(found in part 1)
Solving for t, we find the time taken for the plane to reach the final velocity of 150 m/s:

.Answer:
491.4 nm
Explanation:
The distance between central and first maxima is,

And the distance between screen abnd grating is,

Now the angle can be find as,

Now the grating distance is,

Now with m=1 condition will become,

So,

Therefore the wavelength of laser light is 491.4 nm.
Answer:
-414.96 N
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration


The force the ground exerts on the parachutist is -414.96 N
If the distance is shorter than 0.75 m then the acceleration will increase causing the force to increase