Hi there!
We can use the work-energy theorem to solve.
Recall that:

The initial kinetic energy is 0 J because the crate begins from rest, so we can plug in the given values for mass and final velocity:

Now, we can define work:

Now, plug in the values:

Solve for theta:

find acceleration force divided by Mass
a=f/m
Answer:
Explanation:
Time of flight = 2 x u sinα / g where u sinα is vertical component of projectile's velocity u .
So Time of flight = 2 x vertical component / g
vertical component = constant
g is also constant so
Time of flight will also be constant .
It will remain unchanged .
Answer:
λ = 623.2 nm
Explanation:
We are given;
separation distance; d = 0.195 mm = 0.195 × 10^(-3) m
interference pattern distance; D = 4.85 m
Width of two adjacent bright interference; w = 1.55 cm = 1.55 × 10^(-2) m
Formula for fringe width is given as;
w = λD/d
Where λ is wavelength
Thus;
λ = dw/D
λ = (0.195 × 10^(-3) × 1.55 × 10^(-2))/4.85
λ = 0.0000006232 m
Converting to nm gives;
λ = 623.2 nm