Question

Car A has twice the mass of car B , and car A has the half the kinetic energy of car B . How do their speeds compare?

Answer 1

Speed of car A is half the speed of car B.

Step-by-step explanation:

Kinetic energy,
`KE=(1)/(2)mv^2`

Car A has twice the mass of car B.

`m_A=2m_B`

Car A has the half the kinetic energy of car B

`KE_A=(1)/(2)KE_B`

We have

`KE_A=(1)/(2)KE_B\\\\(1)/(2)m_Av_A^2=(1)/(2)* (1)/(2)m_Bv_B^2\\\\(1)/(2)* 2m_Bv_A^2=(1)/(2)* (1)/(2)m_Bv_B^2\\\\v_A^2=(v_B^2)/(4)\\\\v_A=(v_B)/(2)`

Speed of car A is half the speed of car B.