A(n) 7.6 g object moving to the right at 20 cm/s makes an elastic head-on collision with a 23 g object moving in the opposite direction at 45 cm/is. 7.6 g 20 cm/s 23 g 45 cm/s Find the velocity of the first object immediately after the collision. Answer in units of cm/s.

You want to move a heavy box with mass 30.0 kg across a carpeted floor. you pull hard on one of the edges of the box at an angle 30∘ above the horizontal with a force of magnitude 240 n, causing the box to move horizontally. the force of friction between the moving box and the floor has magnitude 41.5 n . what is the box's acceleration just after it begins to move