Physics

Week 2 Assignment: Case Study - JATO Car

Student Name:

Record the values provided in the assignment and do the calculations. When two fields are provided for a quantity, the number part of the answer goes into the first field and the units in the second field.

Example:
How many centimeters in 1 meter:	100	cm

Useful unit conversions to change data from English units of force, weight in pounds, and speed in MPH to metric units of force in Newtons, mass in kilograms, and speed in meters/second:

1 pound = 4.448 Newtons

1 pound of weight requires 0.4536 kg of mass

1 MPH = 0.44704 m/s

1. Use the estimated thrust of a JATO rocket and the time it fires to predict the change in momentum of the car from the time the rocket starts until it stops. You can use the time given in the story or the shorter time listed in the properties of the 15-KS-1000 solid fuel rocket.

Formula: Change in Momentum = Force x Time

Rocket Thrust in units of Newtons
Time thrust is applied
Impulse
The car’s change in momentum

2. Given the mass of the car plus rocket, use the change in momentum to calculate the change in speed. Formula: 

Mass of car in kilograms
Mass of rocket in kilograms
Total mass of car and rocket in kilograms
Change in speed of car (in m/s)

3. Convert this speed from meters/second to MPH. Then add this to the alleged initial speed when the rocket was fired (assume 50 MPH).

Change in speed of car (in MPH)
Final speed of car after adding initial speed

4. In the field below, discuss one other potentially questionable claim of the original story as reported in the e-mail that might be tested by applying laws of physics.