Atruck moving 11.0 m/s makes a head-on inelastic collision with a stationary 1290 kg car. after, they move 8.75 m/s. what is the mass of the truck ?

5017 kg

Explanation:

Since it is an inelastic collision, the truck and the car move together after the collision. The law of conservation of momentum states that the total momentum before and after the collision is conserved:

where

M is the mass of the truck

is the velocity of the truck before the collision

m = 1290 kg is the mass of the car

is the initial velocity of the car (stationary, so u=0)

v = 8.75 m/s is the final speed of the truck+car after the collision

Solving the equation for M, we can find the mass of the truck: