Two Bodies, a and B, Collide As Shown in Figures a and B Below

1. Two bodies, A and B, collide as shown in Figures a and b below.

Which statement is true? a. They exert equal and opposite forces on each other in (a) but not in (b). a. They exert equal and opposite force on each other in (b) but not in (a). c. They exert equal and opposite force on each other in both (a) and (b). d. The forces are equal and opposite to each other in (a), but only the components of the forces parallel to the velocities are equal in (b). e. The forces are equal and opposite in (a), but only the components of the forces perpendicular to the velocities are equal in (b)

The only force acting on a 2.0-kg object moving along the x axis is shown. If the velocity vx is – 2.0 m/s at t = 0, what is the velocity at t = 4.0 s?

a. –2.0 m/s b. –4.0 m/s c. –3.0 m/s d. +1.0 m/s e. +5.0 m/s

1. Tommy and his skateboard have a combined mass of 50 kg. John and his skateboard total 100 kg. You push each of them with the same force F, but you push Tommy for 2 seconds and John for 1 second. After you finish pushing them,

(a) Tommy is moving faster than John (b) John is moving faster than Tommy (c) they are both moving the same speed (d) there is not enough information to decide about their speeds. 2. A blue car of mass 1500 kg moving at 45 m/s rear-ends a red car of mass 1000 kg which was moving 30 m/s before the collision. If the two cars lock together, what will be their speed immediately after the collision?

(a) 39.0 m/s (b) 37.5 m/s (c) 45.0 m/s (d) 30.0 m/s (e) 39.7 m/s