A rookie quarterback throws a football with an initial upwar

agreseza

agreseza

Answered question

2022-01-16

With an initial upward velocity component of 12.0 m/s and a horizontal velocity component of 20.0 m/s, a novice quarterback tosses a football. Neglect air resistance.
(a) How much time is required for the football to reach the highest point of the trajectory?
(b) How high is this point?
(c) How much time (after it is thrown) is required for the football to return to its original level? How does this compare with the time calculated in part (a)?
(d) How far has the football traveled horizontally during this time?
(e) Draw xt,yt,vxt,and vyt graphs for the motion.

Answer & Explanation

mauricio0815sh

mauricio0815sh

Beginner2022-01-17Added 34 answers

Step 1
Given;
- viy,Chirpy=0ms
- tChirpy=3.50s
- vi,Milada=95.0cms=0.95ms
- θi,Milada=32.0
g=9.80ms2
Step 2
- First of all, we need to find the height of the cliff by using the time the cricket Chirpy takes to reach the ground. So we can use the kinematic formula of vertical displacement.
yf=yi+viyt+12ayt2
- We know that the initial vertical velocity component of Chirpy is zero since it jumps horizontally. So,
yf=yi+0t+12ayt2
- We chose the ground to be the zero level in which y=0,so yf,Ch=0.
0=yi+12ayt2
Step 3
- We can assume that air resistance is negligible, so the vertical acceleration of Chirpy is the free-fall acceleration, thus ay=g
0=yi12t2
- Noting that the initial height of the two crickets is the height of the ckiff, so yi=h.
0=h12t2
- Solving for h;
h=12t2
- Plugging the given;
h=129.803.502
h=60.0m
Step 4
- Now we know the initial height of the two crickets and we know that the air resistance is neglible.
- This means that the horizontal velocity component of both of the two crickets is constant.
- So, to find the horizontal displacement of Milada, we need to find the time it takes to reach the ground.
Step 5
- We can use the kinematic formula of vertical displacement since it is moving under the free-fall acceleration.
yf=yi+viyt+12ayt2
- Notice that ay=g
yf=yi+viyt12t2
- We know that the final position of Malida is the ground in which y=0.
0=yi+viyt12t2
- We know in step 3, that yi=h, so
0=h+viyt12t2
Step 6
- We know that the initial vertical velocity component is given by viy=visinθi. Thus;

SlabydouluS62

SlabydouluS62

Skilled2022-01-18Added 52 answers

Draw a diagram to illustrate the problem as shown below.
The ball is thrown from A, rises to a maximum height at B, and returns to the original level at C.
Given:
v=12.0ms, vertical component of launch velocity
u=20ms, horizontal component of launch velocity.
Note that g=9.8ms2, the acceleration due to gravity.
Wind resistance is ignored.
Part a.
The time, t, required to reach B from A is given by
0 = 12 - 9.8task
t=129.8=1.2245s
Answer: The time is 1.225 s (nearest thousandth)
Part b.
The height attained is
h=121.2245059.81.22452
=7.347m
Answer: The height attained is 7.35 m (nearest hundredth) above A.
Part c.
When the ball returns the level of point A or C at time t,
0=12t0.59.8t2
t(124.9t)=0
t=0(p A), or
t=4.92=2.45s (point C)
Notice that 2.452=1.225s, which is equal to the time to reach B from A.
Answer:
The time taken to travel from A to C is 2.45 s.
This time is twice the time taken to travel from A to B.
Part d.
The horizontal distance traveled from A to C is
d=202.45=49m
Answer: 49 m
Part e.
x(t) = 20task for horizontal travel
y(t)=12t4.9t2 for vertical travel
vy(t) = 12 - 9.8task for vertical velocity
vx(t)=20 for horizontal velocity.
Graphs of x-t, y-t, vx-t, vy-t are shown below.

alenahelenash

alenahelenash

Expert2022-01-23Added 556 answers

Time is required for the football to reach the highest point of the trajectory is 1.22 s Further explanation A rookie quarterback throws a football with an initial upward velocity component of 12.0m>s and a horizontal velocity component of 20.0m>s. ignore air resistance. (a) how much time is required for the football to reach the highest point of the trajectory? According to the kinematic equation the time required to reach max displacement is: vfy=viygt1 By substitution we get t1=129.8=1.22s (b) how high is this point? The max point is given by the equation vfy2=viy22gymax By substituting ymax=xiy22g=12229.8=7.35m (c) how much time (after it is thrown) is required for the football to return to its original level? how does this compare with the time calculated in part (a)? y(t)=y0+vyit12gt2 Where: y(t)=y0=0 because the final position is the initial position is equal to zero t is total time required to cover the total displacement viy=12m/s By substitution we get 0=0+12t4.9t2 t=2.45s (d) how far has the football traveled horizontally during this time? According to projectile motion the horizontal displacement is given by x=vx By substitution we get (e) draw x-t, y-t, vx-t, and vy-t graphs for the motion. Attached the graphs

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