Answer:
t = 1.16 s.
Explanation:
Given,
speed of conveyor belt, v = 3.2 m/s
coefficient of friction,f = 0.28
Using newton second law
f = ma
and we also know that frictional force
f = μ N
f = μ m g
equating both the force equation
a = μ g
a = 0.28 x 9.81 
a = 2.75 m/s²
Using Kinematic equation
v = u + at
3.2 = 0 + 2.75 x t
t = 1.16 s.
Time taken by the box to move without slipping is 1.16 s. 
 
        
             
        
        
        
Answer:
a) u = 30.29 m/s
b) t = 2.09 s
Explanation:
given,
velocity = 45 m/s
angle (θ) = 50°
horizontal velocity = 45 cos 50°
time taken to reach 150 m.
times = 
t  =  5.19 s
a) height of arrow 



s = 46.78 m
v² - u² = 2 g s
u² = 2 × 9.81 × 46.78
u = 30.29 m/s
b) time taken by the apple = 
                                              = 3.09 s
time after which it has to be thrown = 5.19-3.09 = 2.1 s
 
        
             
        
        
        
<h2>
Answer: Infrared light</h2>
A dark nebula is a cloud of dust and cold gas, which does not emit visible light and hides the stars it contains.
These types of nebulae are composed mainly of the hydrogen they obtain from nearby stars, which is their fuel.
It is using infrared light that we can "observe" and analyze in detail what happens in the inner parts of these nebulae.
 
        
        
        
A. very small objects behave like like particles.
        
                    
             
        
        
        
Answer:
Explanation:
separation between two gaps, d = 5 cm 
angle between central and second order maxima, θ = 0.52°
use 
d Sinθ = n λ
n = 2 
0.05 x Sin 0.52° = 2 x λ
λ = 2.27 x 10^-4 m 
λ = 226.9 micro metre