Practice Problems for 1st Semester Exam
Practice Problems for 1st Semester Exam
Practice Problems for 1st Semester Exam
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
6. Troy, a Pinellas county sheriff is trying to determine the speed of a car that went off the Howard Franklin<br />
bridge on a rainy night and landed in the water 5 m below. The car landed 10 m horizontally from the<br />
bridge in the water. How fast was the car going when it left the road?<br />
PS: the driver was not hurt , however Troy gave him a ticket <strong>for</strong> reckless driving!<br />
dy = 5m dx = 10m vx = ? vx = dx / t don’t know t; solve <strong>for</strong> t first<br />
t = 2dy / g t = 2(5m) /(10 m/s 2 ) t = 10m/ 10 m/s 2 t = 1s<br />
vx = dx / t vx = (10m) / 1s vx = 10 m/s<br />
7. Mrs. Peck’s class is trying to calculate where a flour sack would land if dropped from a moving airplane.<br />
The plane would be moving horizontally at a constant speed of 50 m/ s at an altitude of 200m. Neglecting<br />
air resistance, how far horizontally from the dropping point would they predict the flour sack would land?<br />
vx =50 m/s dy = 200m dx = ? dx = vx t don’t know t; solve <strong>for</strong> t first<br />
t = 2dy / g t = 2(200m)/10 m/s 2 t = 400m /10 m/s 2 t = 40 s 2 t = 6.32 s<br />
dx = (50 m/s) (6.32 s) dx = 316 m<br />
8. A pull of 6N causes a 0.5 kg object to move at a constant velocity. Complete the diagram.<br />
a. Fn = 5N b.<br />
Ff = c. 6N constant velocity Fapp = Ff & Fnet = 0N<br />
d. Fapp = 6N<br />
m = 5kg … Fg = mg … Fg = (.5kg)(10m/s<br />
Fg e. =<br />
f.<br />
m = _______<br />
g.<br />
h.<br />
2 ) = 5N<br />
5N<br />
.5 kg Fg = Fn … Fn = 5N<br />
0N a = Fnet/ m a = 0N/ .5kg = 0 m/s 2<br />
Ff =<br />
c.<br />
a = _______<br />
a. Fn = b.<br />
Fg e. =<br />
d. Fapp =<br />
f.<br />
m = _______ 8 kg Fnet = Fapp – Ff = 30N – 10N = 20N<br />
g.<br />
h.<br />
0 m/s 2<br />
9. An applied <strong>for</strong>ce of 30N is used to accelerate an object with a weight of 80N to the right across<br />
a frictional (with friction) surface. The object encounters 10N of friction. Complete the diagram.<br />
10N<br />
a = _______<br />
80N Fg = Fn Fn = 80N<br />
80N<br />
30N Fg = mg m = Fg/ g = 80N/ 10 m/s 2 = 8kg<br />
20N a = Fnet / m a = 20N/ 8kg a = 2.5 m/s 2<br />
2.5 m/s 2