1. At a given instant of time, a car and a truck are traveling side by side in adjacent lanes of a highway. The car has a greater velocity than the truck. Does the car necessarily have a greater acceleration? Explain.
2.NASA has developed Deep-Space 1 (DS-1), a spacecraft that is scheduled to rendezvous with the asteroid named 1992 KD (which orbits the sun millions of miles from the earth). The propulsion system of DS-1 works by ejecting high-speed argon ions out the rear of the engine. The engine slowly increases the velocity of DS-1 by about 19.0 m/s per day.
(a) How much time (in days) will it take to increase the velocity of DS-1 by 11200 m/s?
______________ days
b) What is the acceleration of DS-1 (in m/s2)?
______________ m/s2
3.Two motorcycles are traveling due east with different velocities. However, four seconds later, they have the same velocity. During this four-second interval, motorcycle A has an average acceleration of 1.7 m/s2 due east, while motorcycle B has an average acceleration of 3.0 m/s2 due east. By how much did the speeds differ at the beginning of the four-second interval?
_________________ m/s
Which motorcycle was moving faster?
_________________
One Response
1. The car does not necessarily have a greater acceleration. It could simply have overtaken the truck while each was moving at its own constant speed.
2.
a. (11 200 m/s) / (19.0 m/s/d) = 589 d
b. (19.0 m/s/d) / (86 400 s/d) = 2.2×10^-4 m/s²
3. The difference in their accelerations is 3.0 – 1.7 = 1.3 m/s². In four seconds, 1.3 m/s² changes the speed by (4)(1.3) = 5.2 m/s.
Motorcycle A was initially faster but was overtaken by B with its greater acceleration.