Acceleration = (velocity final-velocity initial)/ time
where
velocity final = 135 km/hr x 1 hr /3600 s x 1000m/1km
= 37.5 m/s
velocity initial = 35 km/hr x 1hr /3600 s x 1000 m/1 km
= 9.72 m/s
a) acceleration = 2.646 m/s^2
b) acceleration in g units = (2.646m/s^2)/(9.8m/s^2)
= 0.27 units
As we know that friction force on box is given by

here we know that

here we have
m = 12 kg

so now we have

now we will have


so it required minimum 49 N(approx) force to move the block
Answer:
D
Explanation:
Two plane mirrors are inclined at 70∘. A ray incident on one mirror at incidence angle θ after reflection falls on the second mirror and is reflected from there parallel to the first mirror, The value of θ is. ∴(θ)=50∘.
Answer:

Explanation:
Given data
Baseball mass m₁=0.15 kg
initial speed v₁=0
Bullet mass m₂=0.032 kg
final speed v₂=230 m/s
To find
height h=?
Solution
From conservation of momentum we know that

Now from the conservation of mechanical energy