Question

A block of mass 15 kg is sliding along the ice at a constant speed of 4.0 m/s. Just ahead of it is a block of mass 23 kg sliding in the same direction at a constant speed of 3.6 m/s. When the two blocks collide, the 23 kg block travels at a new speed of 5.2 m/s. What is the new speed of the 15 kg block?

Answer 1

1.55 m/s

Step-by-step explanation:

Following the law of conservation of linear momentum, momentum is conserved hence the sum of initial and final momentum are the same

p=mv where p is momentum, m is the mass of object and v is the velocity of the same object.

`m_1v_1+m_2v_2= m_1V_3+ m_2V_4` where m and v represent mass and velocity respectively, subscripts 1 and 2 represent initial speed of 15 Kg block and 23 kg block respectively, subscripts 3 and 4 represent final speed of 15 Kg block and 23 kg block respectively.

By substitution

`15*4+(23*3.6)=23*5.2+15V_3\\15V_3=23.2\\V_3=1.546666667\approx 1.55 m/s`