Question

Christian throws the ball at a speed of 88 km / h vertically in a hanging bag, where it also stays. The mass M of the empty bag can be changed by adding a suitable amount of lead pellets there.
a) The bag hangs on a light and unstretchable string, the top of the string is attached to a branch around which the string can rotate. Length of string l = 1.6. Determine what the bag's mass should be like, so that the string will rise exactly horizontally

b) the mass of the bag is selected to be M = 350 g and is attached to the lower end of the homogeneous rod. Rod mass m = 150 g and length l = 1.6. At the top of the rod there is an axis around which the rod can rotate smoothly. Determine how high the bottom of the rod and the bag will rise.

all the info is told above

7n

Answer 1

Let us first calculate the velocity of bag+ ball using conservation of momentum

As the mass of ball is not given, we will assume it to be m,

m × 88 = (M+m) v

v = 88m /( M + m)

Now conserving the energy for the system as whole of Kinetic energy gets converted into Potential energy

(M+m) g × 1.6 = 1/2 (M+m) v^2

Put the value of v as above and you can find Me

b) To find h, the velocity will remain the same

(350 + m) g × h = 1/2 ( 350 + m) v^2

From here, we can find h