Question

two small balls are suspended on parallel threads of the same length so that they touch each other in the vertical position. the mass of the first ball is 0.4kg and the mass of the second ball is 200g. the first ball is deflected so that its centre of mass rises to a height of 6cm and it is then released. to what maximal height will the 200g ball rise if the collision is elastic?

Answer 1

Answer: 12cm

Explanation:

Since first ball is raised to a height h1= 6cm, it gains a potential energy(PE1). On release, this PE1 is converted to kinetic Energy (KE1). This KE1 impact it energy on ball 2 ans it rise also. Since collision is elastic.

KE1 = KE2 ....> PE1 = PE2

m1 ×g × h1 = m2 × g× h2

h2 = m1×h1/m2

h2 = 0.4 × 0.06/0.2

h2 = 0.12m = 12cm