Physics_50_Proficiency_Test_2s - Physics 50 Proficiency...

Physics 50 Proficiency Test 2 (sample)
(Time: 15 minutes) 25 points
By Todd Sauke
Name ________________________ Section # ________
When an object flies freely (with no impedance, obstruction or wind resistance) in the
presence of a constant gravitational field, the motion is called "projectile motion". Near
the surface of the Earth, the gravitational field is approximately constant and results in
projectile motion of freely flying bodies with a constant acceleration of 9.80 m/s
2
(directed downward) when air resistance can be neglected. The kinematic equations for
constant acceleration motion in the x direction are: (For constant acceleration motion in
the y direction, we can simply substitute y for x .)
v = v
0
+ a t x - x
0
= ½(v
0
+v) t v
2
= v
0
2
+ 2a ( x – x
0
) x = x
0
+ v
0
t + ½ at
2
A football player kicks (at t = 0) a football (initially on the ground) down the football
field toward the goal post with an initial speed of 27.8 yards per second at an angle of
52 º above the horizontal. The football subsequently strikes the horizontal field goal
cross bar, which has a height of 10 feet.