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).
Laurentia, also called the North American Craton, is a huge continental craton. It<span> forms the ancient </span>geological<span> core of the </span>continent of North America.<span> It is made up of present day North America and Greenland. About 300 million years ago, it collided with the southern hemispheric continent of </span>Gondwana<span> and formed the supercontinent called Pangaea.</span><span> </span>
Answer:
The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength. Speed shows how long it takes for wavelengths to travel.