A 2 kg cart moving at 3 m/s collides with a 1 kg cart at rest, and they stick together. What is their common speed?
Answer and explanation
Correct answer: B. 2 m/s
- Step 1: Momentum is conserved: kg m/s before the collision. Step 2. After it, the mass is 3 kg, so m/s. Answer: 2 m/s. Why not the others: 3 m/s ignores the added mass, 1 m/s divides by 6, and 4.5 is more than the original speed.
Practise more Physics.
Free questions with an explanation for every one, and full timed Uzbekistan National Certificate (Milliy sertifikat) mock tests.
More Physics questions
- What is the SI unit of force?
- What is the approximate speed of light in a vacuum?
- A car starts from rest and accelerates at 3 m/s. What is its speed after 5 s?
- A resistor of 4 ohms is connected to a 12 V battery. What current flows?
- What force acts on a 5 kg object that accelerates at 2 m/s?
- What is the kinetic energy of a 2 kg object moving at 3 m/s?