PHYSICSS PLEASE HELP

A baseball player hits a homerun, and the ball lands in the left field seats, which is 103m away from the point at which the bal

Sati [7]

(a) The ball has a final velocity vector

$\mathbf v_f=v_{x,f}\,\mathbf i+v_{y,f}\,\mathbf j$

with horizontal and vertical components, respectively,

$v_{x,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\cos(-38^\circ)\approx16.2\dfrac{\rm m}{\rm s}$

$v_{y,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\sin(-38^\circ)\approx-12.6\dfrac{\rm m}{\rm s}$

The horizontal component of the ball's velocity is constant throughout its trajectory, so $v_{x,i}=v_{x,f}$ , and the horizontal distance x that it covers after time t is

$x=v_{x,i}t=v_{x,f}t$

It lands 103 m away from where it's hit, so we can determine the time it it spends in the air:

$103\,\mathrm m=\left(16.2\dfrac{\rm m}{\rm s}\right)t\implies t\approx6.38\,\mathrm s$

The vertical component of the ball's velocity at time t is

$v_{y,f}=v_{y,i}-gt$

where g = 9.80 m/s² is the magnitude of the acceleration due to gravity. Solve for the vertical component of the initial velocity:

$-12.6\dfrac{\rm m}{\rm s}=v_{y,i}-\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)\implies v_{y,i}\approx49.9\dfrac{\rm m}{\rm s}$

So, the initial velocity vector is

$\mathbf v_i=v_{x,i}\,\mathbf i+v_{y,i}\,\mathbf j=\left(16.2\dfrac{\rm m}{\rm s}\right)\,\mathbf i+\left(49.9\dfrac{\rm m}{\rm s}\right)\,\mathbf j$

which carries an initial speed of

$\|\mathbf v_i\|=\sqrt{{v_{x,i}}^2+{v_{y,i}}^2}\approx\boxed{52.4\dfrac{\rm m}{\rm s}}$

and direction θ such that

$\tan\theta=\dfrac{v_{y,i}}{v_{x,i}}\implies\theta\approx\boxed{72.0^\circ}$

(b) I assume you're supposed to find the height of the ball when it lands in the seats. The ball's height y at time t is

$y=v_{y,i}t-\dfrac12gt^2$

so that when it lands in the seats at t ≈ 6.38 s, it has a height of

$y=\left(49.9\dfrac{\rm m}{\rm s}\right)(6.38\,\mathrm s)-\dfrac12\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)^2\approx\boxed{119\,\mathrm m}$

6 0

4 years ago

which of the following statements is correct when describing the forces at work on a bridge a. wires are in tension B. large pos

stiv31 [10]

Answer:

All the statements are true

Explanation:

A) Wires are in tension.

It is true because the loads exerted on the bridge are taken by each of the cables of the bridge. these cables transmit the force to the pillars or columns of the bridge. (check the image 01)

B) Large posts are in compression.

It is true each of the loads of the cables is tension, are transmitted to the columns of the bridge, in this way the balance will be maintained (check the image 01)

C) The bridge deck is both in tension and compression.

Yes it is true, the superior part of the deck will be in compression and the inferior part will be in tension, this can be seen in the image 02

8 0

3 years ago

During an experiment, a scientist places a heat lamp above a bowl of water and uses the lamp to heat up the water. How does heat

alexandr402 [8]

Answer:

radiation

Explanation:

6 0

3 years ago

Read 2 more answers

To meet a U.S. Postal Service requirement, employees' footwear must have a coefficient of static friction of 0.5 or more on a sp

Vlada [557]

Answer:

the minimum time interval is 0.77 seconds

Explanation:

given data

coefficient of static friction = 0.5

coefficient of static friction shoes= 0.825

travel s = 2.40 m

to find out

what is the minimum time interval

solution

we know newton 2nd law

force = mass × acceleration

and

force acting on person due to friction

force = coefficient of static friction shoes × mg

so we can say

coefficient of static friction shoes × mg = ma

so

a = coefficient of static friction shoes × g

and we know g is 9.8 m/s²

so

distance formula by kinematic relation

distance = ut + 0.5 × at²

here put a value and u is zero because initial speed

2.40 = 0 + 0.5 × coefficient of static friction shoes × g× t²

2.40 = 0.5 × 0.825 × 9.8 × t²

t = 0.77 s

the minimum time interval is 0.77 seconds

5 0

4 years ago

Describe the limitations of the free body diagrams.

Olenka [21]

Answer:

Free-body diagrams are defined as the diagram that represents the direction and magnitude of all forces that act on an object.

There are some limitations of the free-body diagrams, that are:

The free-body diagram is based on coordinate system that increases the complexity of the diagram.
There are lot of forces acting on an object such as friction, gravity, drag, tension, and normal force and to calculate the end result, it is important to determine the correct direction of all the forces otherwise wrong direction of any one of the force can give the wrong answer.
Free-body diagrams do not depend on the size and shape of the body, that is why unable to calculate the rotation and torque.

8 0

3 years ago