A 4400-kg open railroad car coasts at a constant speed of 9.00 m/s on a level tr

Question

A 4400-kg open railroad car coasts at a constant speed of 9.00 m/s on a level track. Snow begins to fall vertically and fills the car at a rate of 3.20 kg/min Ignoring friction with the tracks, what is the speed of the car after 85.0 min ?

A 22-g bullet traveling 245 m/s penetrates a 1.5 kg block of wood and emerges going 150 m/s If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?

A meteor whose mass was about 2.0×108kg struck the Earth (mE=6.0×1024kg) with a speed of about 23 km/s and came to rest in the EarthWhat was the Earth's recoil speed (relative to Earth at rest before the collision)?

Explanation / Answer

initial kinetic energy=0.5*m*v^2=0.5*4400*9^2=178200 J

after 85 min mass of ice=85*3.2=272 kg

total mass=4400+272=4672 kg

since kinetic energy will remain conserved

0.5*4672*v^2=178200 J

where v is velocity after 85 min

v=8.73 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.