Arturo O. answered • 11/26/19
Experienced Physics Teacher for Physics Tutoring
m = mass of car = 100 kg
M = mass of truck = 400 kg
Initial conditions:
v = velocity of car = -45 m/s (take left as negative direction)
u = velocity of truck = +25 m/s
Final condition:
w = final velocity of car + truck
mv + Mu = (m + M)w
w = (mv + Mu) / (m + M)
Plug in the values of m, M, v, and u. Make sure you put in the correct signs for v and u. If w comes out negative, they move together to the left. If w comes out positive, they move together to the right.
Arturo O.
I get that answer too. Even though the truck is moving slower than the car, it is so much more massive that it dominates the net direction of momentum.11/26/19
Mark H.
thanks for pointing out my error!!11/27/19
Arturo O.
You are welcome, Mark.11/27/19
Nancy L.
Thank you both!11/27/19
Nancy L.
Any guidance on these? Nicole and Johnny are riding their bicycles and experience a collision. Nicole experiences a force of80N during the 0.6 second collision. Nicole’s change in velocity was 0.8 m/s. Johnny’s mass is twice that of Nicole’s. What is the magnitude of the change in velocity Johnny experienced? a. 0.8 m/s . b. 1.6 m/s c. 0.4 m/s . d. 48 m/s Two toy cars with 1 kg mass are on a frictionless surface. One toy car is stationary while the second is rolled towards and collides with the first toy car. What could you change about their initial conditions to increase the speed after they collide and stick together? a. Increase the stationary cars mass to more than 1 kg b. Increase the moving cars mass to more than 1 kg . c. Decrease the moving cars initial speed . d. Roll both cars towards each other with exactly the same speed11/27/19
Nancy L.
So is the answer 11m/s right for resulting velocity11/26/19