1. A car is driving along a straight section of highway between Oklahoma City and Tulsa. At one point in time, the car is 50 miles from Tulsa. At a later point in time, it's 40 miles from Tulsa. What is its displacement?
Answer:
10 miles = 16 kilometers
2. An aircraft flies 20 km on a course of 030 degrees, then 30 km on a course of 270 degrees. What is its distance and bearing from its takeoff point? (Hints: Make a sketch. Convert flight legs to Cartesian vectors in standard position. See the "Overview of Vectors" handout.)
Answer:
Distance is 50 kilometers because if flew 20 kilometers in one direction
And then flew 30 kilometers to the other direction.
20+30=50 kilometers
The bearing from the takeoff point is 270+30 = 300 degrees.
3. A snail travels for a year on a straight line, covering 2.7 km. What is its average velocity, in m/s?
Answer:
We need to convert years into seconds. 1 year will be 365*24*60*60= 31 104 000 seconds.
Now let’s convert kilometers into meters:
2.7 kilometers = 2700 meters.
Average velocity is V=S/T = 2700/31104000=0,0000086 m/s.
4. The parachute on a top fuel dragster slows the car from 300 mph to 100 mph in 5 seconds. What is the average deceleration, in gs (acceleration of gravity)? (Hint: Use an online conversion app, and work in MKS [metric] units.0
Answer:
Deceleration = (Initial speed – final speed) / total time taken = (300 – 100) / 5 = 40 miles hour second
40 miles hour second = 17.8 m/s2
5. A small powder charge propels a shoulder-launched antitank missile from its tube at 10 m/s. At 0.3 seconds after launch, the rocket motor ignites and accelerates the missile at 50m/s2. How far (from the tube) has the missile traveled after two seconds? (Hint: Calculae two distances, and add them together; the distance before the rocket ignites, and the distance after.)
Answer:
Distance = distance1 + distance2;
Distance 1 = 10 * 0.3 = 3 meters;
Distance2 = 50 * 1.7 = 85 meters;
We used 1.7 seconds because the whole period of time is 2 seconds and 0.3 seconds were spent on the distance1.
Total distance = 85 + 3 = 88 meters.
