Precalculus

Pre-calculus Physics Project: posted 2/18/03

Force = Mass x Acceleration !

Students calculated the mass of a pickup by measuring the force required to push it, and the resulting acceleration.

Mass = Force / Acceleration

Force was held constant by using bathroom scales at 20 lbs. per student pushing.

F = 3 pushers x 20 lbs x (1 kg/ 2.2 lbs) x (9.8 m/s/s) = 267 N

Acceleration was measured by marking the pickup's location at 3 second intervals.

Velocity = Distance / Time ( Ten 3-second intervals were measured)

Interval	Distance (meters)	Velocity (meters/sec)
1	0	0
2	1.56	0.52
3	2.22	0.74
4	2.06	0.69
5	2.82	0.94
6	2.89	0.94
7	3.00	1.00
8	2.84	0.95
9	2.23	0.74
10	2.34	0.78
11	2.36	0.79

Acceleration = Final Velocity - Initial Velocity ( For each 3-second interval.)

Interval	Acceleration meters/s/s
1	0
2	0.52
3	0.22
4	-0.05
5	0.25
6	0.02
7	0.04
8	-0.05
9	-0.21
10	0.04
11	0.01

Accelerations were averaged to find a mean value for A. ( A = 0.08 m/s/s )

Mass = Force / Acceleration

Mass = 267 N / (0.08 m/s/s) = 3336 kg

Weight = 3336 kg x (2.2 lbs/kg) =7054 lbs

The student drove to the local grain elevator and had the pickup weighed.

The official result was 6640 lbs.

% Error = (Calculated Value - Actual Value) / Actual Value

% Error = ((7054 - 6640) / 6640 ) x 100 = +6.2%

Students completed calculations and wrote an essay about the experience.

Calculations based on 2003 data.

Email: cindy.kroon@k12.sd.us K12 Data Center DDN Common Core Standards (CCSSM)