EF 157 - Recitation 1-8 - Page 1 of 5
Note, all numbers are assumed to be accurate to 3 SF
1) The flight path of a jet aircraft as it takes off is
2
given by the parametric equations x = 1.25t
3
and y = 0.03t , where t is the time after take-off
measured in seconds and x and y are given in
meters. Determine the magnitude of the total
acceleration on the plane at t = 40 s.
2) A test car starts from rest on a flat, straight course. It is
subjected to the acceleration given in the diagram at right.
Determine the time t when the car comes to rest again.
EF 157 - Recitation 1-8 - Page 2 of 5
Note, all numbers are assumed to be accurate to 3 SF
3) During an EF 101 lecture, Dr. Raman decides to throw a tennis ball at one of the lights in the ceiling. He
stands directly below the light and throws the tennis ball vertically. The light is 42 ft above the floor and Dr.
Raman releases the ball 7 ft above the floor. What is the minimum velocity that Dr. Raman must throw the ball
in order to hit the light?
4) A car starts from rest on a flat circular track and slowly increases its speed. The tires will begin to slip on the
pavement when the acceleration reaches 1/3g. If the car begins to slide at 45 MPH, calculate the radius of the
circular track.
EF 157 - Recitation 1-8 - Page 3 of 5
5) The baseball player A hits the
baseball with a speed of vA = 40 ft/s at
an angle of 60o from the horizontal.
Player B takes ¼ of a second to
respond before he begins to run with a
constant speed vB. Player B catches
the ball at C at an elevation that is 3 ft
higher than the elevation at which
Player A hit the ball. Determine:
a) the distance d,
b) the speed at which Player B must
run (i.e., vB),
c) the velocity of the baseball relative
to Player B right before he catches
the ball at C.
Note, all numbers are assumed to be accurate to 3 SF
EF 157 - Recitation 1-8 - Page 4 of 5
Note, all numbers are assumed to be accurate to 3 SF
6) Show all work on this problem, clearly indicating the final answers.
Given: Matlab Man decides to perform an “Evil Knievil” trick and jump a KAT bus as shown. At the bottom of
the ramp (point A), Matlab Man’s speed is 15 MPH. He puts his foot on the gas pedal and accelerates at a
constant rate a until he leaves the ramp at point B. Matlab Man then lands on the ground at point C.
75 ft
15o
KAT
125 ft
Required:
a) Determine the magnitude of the constant acceleration a of Matlab Man as he goes up the ramp.
b) Determine the magnitude and direction Matlab Man’s velocity just before he hits the ground at point C.
EF 157 - Recitation 1-8 - Page 5 of 5
Note, all numbers are assumed to be accurate to 3 SF