Answer:
The velocity of the truck after this elastic collision is 15.7 m/s
Explanation:
It is given that,
Mass of the car, 
Mass of the truck, 
Initial velocity of the car,
Initial velocity of the truck, u₂ = 0
After the collision the velocity of the car is, v₁ = -11 m/s
Let v₂ is the velocity of the truck after this elastic collision. Using the conservation of momentum as :

So, the velocity of the truck after this elastic collision is 15.7 m/s. Hence, the correct option is (c).
Answer:
Atomic radius decreases moving from left to right across a period.
Explanation:
When we move left to right across a period, the size of atoms generally decreases. It is because within the period the outer electrons are in same valence shell and the number of electrons and proton increases moving from left to right across the the period. It increases the effective nuclear charge resulting in the increased attraction of electron to the nucleus that causes the decreased radius of the atoms.
Answer:
9.17 m/s^2
Explanation:
Formula for force is given by
F = m*a
where F is the force in newton
m is the mass of body in KG
and
a is the acceleration of body on m/s^2
_______________________________________________
Given
F = 11,000
mass = 1,200 Kg
we have to find value of acceleration
using
F = m*a
11,000 = 1200*a
=> a = 11,000 /1200 = 9.17
Thus, the acceleration of a car is 9.17 meter per second square