Alab cart with a mass of 15 kg is moving with constant velocity, v, along a straight horizontal track. a student drops a 2 kg mass into it from directly above, and the cart continues moving. which equation best represents the horizontal momentum in this situation? 15vi  + 2vi  = 15vf  + 2vf 15vi  + 2(0)  = 15vf  + 2vf 15vi  + 2(0)  = (15  + 2)vf 15vi  + 2vi  =  (15  + 2)vf

15vi + 2(0) = (15 + 2)vf

Explanation:

Before the mass is dropped inside the cart, the mass has zero horizontal velocity, so its momentum is

while the momentum of the cart is

So, the total momentum at the beginning is

15vi + 2(0)

After the bag has been dropped into the cart, the two objects move together, so they have new mass (15+2) kg and the mote at the same velocity vf, so their momentum is

(15 + 2)vf

Since momentum is conserved, we can equalize the two expressions, and we get

15vi + 2(0) = (15 + 2)vf

explanation: in any substance/object, the particles inside it (atoms/molecules) constantly move in random directions and with random speeds (this motion is called brownian motion). as a result, the particles have some kinetic energy (which is proportional to the temperature of the substance).

explanation:

have a great day!

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2