A person weighing 60 kg moves towards a cart weighing 30 kg and jumps on it. What was the speed
A person weighing 60 kg moves towards a cart weighing 30 kg and jumps on it. What was the speed of the cart if the speed of the person at the moment of the jump was 2 m / s, and the speed of the cart was 1 m / s
mh = 60 kg.
mt = 30 kg.
Vch = 2 m / s.
Vt = 1 m / s.
Vт “-?
Let’s write the law of conservation of momentum.
Before the jump, the total impulse of the person and the cart is: mh * Vh – mt * Vt.
The sign “-” because the speed of the person and the cart are directed in the opposite direction.
Impulse of the person and the cart after the jump: (mh + mt) * Vt “.
mh * Vh – mt * Vt = (mh + mt) * Vt “.
Vt “= (mh * Vh – mt * Vt) / (mh + mt).
VT “= (60 kg * 2 m / s – 30 kg * 1 m / s) / (60 kg + 30 kg) = 1 m / s.
Answer: the trolley speed became Vt “= 1 m / s.