$A$ car of mass $1000 \, kg$ moving with a velocity of $15 \, m/s$ collides with a tree and comes to rest in $5 \, s$. What will be the force exerted by the car on the tree?

(3000 N) Given:
Mass of the car $(m) = 1000 \, kg$
Initial velocity of the car $(u) = 15 \, m/s$
Final velocity of the car $(v) = 0 \, m/s$ (since it comes to rest)
Time taken $(t) = 5 \, s$
Using Newton's second law of motion,the force exerted by the tree on the car is given by:
$F = m \times a = m \times \frac{(v - u)}{t}$
Substituting the values:
$F = 1000 \times \frac{(0 - 15)}{5}$
$F = 1000 \times (-3) = -3000 \, N$
The negative sign indicates that the force exerted by the tree on the car is in the opposite direction of motion.
According to Newton's third law of motion,the force exerted by the car on the tree is equal in magnitude but opposite in direction to the force exerted by the tree on the car.
Therefore,the force exerted by the car on the tree is $3000 \, N$.