AvrGang
Sep28-07, 11:15 AM
1. The problem statement, all variables and given/known data
A stunt man drives a car at a speed of 20 m/s off a 30-m-high cliff.
The road leading to the cliff is inclined upward at an angle of 20(degrees).
a. How far from the base of the cliff does the car land?
b. What is the car's impact speed?
2. Relevant equations
3. The attempt at a solution
Here is my solving:
Vix=Vicos@
=20cos20
=18.8m/s
Viy=Visin@
=20sin20
=6.84m/s
a) How far from the base of the cliff does the car land?
x=Vix t
x=18.8t ------(1)
y=Viy t - 1/2gt^2
-30=6.84t-0.5(9.8)t^2
-4.9t^2+6.84t+30=0 (divide this by -4.9)
t^2-1.39t+30=0
From this equation we can find t then sustitute its magnitude in equation 1, so we can find x
b)speed=sqrt((Vfx)^2+(Vfy)^2)
A stunt man drives a car at a speed of 20 m/s off a 30-m-high cliff.
The road leading to the cliff is inclined upward at an angle of 20(degrees).
a. How far from the base of the cliff does the car land?
b. What is the car's impact speed?
2. Relevant equations
3. The attempt at a solution
Here is my solving:
Vix=Vicos@
=20cos20
=18.8m/s
Viy=Visin@
=20sin20
=6.84m/s
a) How far from the base of the cliff does the car land?
x=Vix t
x=18.8t ------(1)
y=Viy t - 1/2gt^2
-30=6.84t-0.5(9.8)t^2
-4.9t^2+6.84t+30=0 (divide this by -4.9)
t^2-1.39t+30=0
From this equation we can find t then sustitute its magnitude in equation 1, so we can find x
b)speed=sqrt((Vfx)^2+(Vfy)^2)