1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
german
3 years ago
8

A quarterback throws a football toward a receiver with an initial speed of 20 m/s at an angle of 30∘ above the horizontal. At th

at instant the receiver is 20 m from the quarterback. In (a) what direction and (b) with what constant speed should the receiver run in order to catch the football at the level at which it was thrown?
Physics
2 answers:
Genrish500 [490]3 years ago
8 0

Answer:

a. The runner must run 15.35 m in the direction of the ball. b. 7.52 m/s

Explanation:

This is an example of projectile motion. We first calculate the range of the football to know where it is going to land.

Given,

initial speed of football,u = 20 m/s

Angle of projection, θ = 30°

a. We calculate the range R = u²sin2θ/g = 20²sin(2 × 30)/9.8 = 400sin60/9.8 = 400 × 0.8660/9.8 = 346.41/9.8 = 35.348 m ≅ 35.35 m

Since the receiver starts 20 m from the quarterback, the distance he runs in order to catch the ball is d = (35.35 - 20) m = 15.35 m.

So the runner must run 15.35 m in the direction of the ball.

b. The time it takes him to run the distance d = 15.35 m and catch the ball is the time it takes the projectile to land at the height he catches the ball which is given by t = 2usinθ/g = (2 × 20 × sin30)/9.8 = (40 × 0.5)/9.8 = 20/9.8 = 2.041 s ≅ 2.04 s

To find the constant speed at which the receiver must run in order to catch the ball at the same level of throw, we use s = vt + 1/2at²

since a = 0 (constant speed), s = vt ⇒ v = s/t

s = d = 15.35 m and t = 2.041 s

v = 15.35 m/2.041 s = 7.521 m/s ≅ 7.52 m/s

lana66690 [7]3 years ago
7 0

Answer:

a) In order to catch the ball at the level at which it is thrown in the direction of motion.

b)Speed of the receiver will be 7.52m/s

Explanation:

Calculating range,R= Vo^2Sin2theta/g

R= (20^2×Sin(2×30)/9.8 = 35.35m

Let receiver be(R-20) = 35.35-20= 15.35m

The horizontal component of the ball is:

Vox= Vocostheta= 20× cos30°

Vox= 17.32m/s

Time taken to coverR=35.35m with 17.32m/s will be:

t=R/Vox= 35.35/17.32

t= 2.04seconds

b)Speed required to cover 15.35m at 2.04seconds

Vxreciever= d/t = 15.35/2.04 = 7.52m/s

You might be interested in
8459299
sergeinik [125]

Answer:

Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy

3 0
2 years ago
for any object suspended by any number of ropes, wires, or chains, how is the total amount of tension (tension in each rope adde
Sveta_85 [38]

Answer:

To calculate the tension on a rope holding 1 object, multiply the mass and gravitational acceleration of the object. If the object is experiencing any other acceleration, multiply that acceleration by the mass and add it to your first total.

Explanation:

The tension in a given strand of string or rope is a result of the forces pulling on the rope from either end. As a reminder, force = mass × acceleration. Assuming the rope is stretched tightly, any change in acceleration or mass in objects the rope is supporting will cause a change in tension in the rope. Don't forget the constant acceleration due to gravity - even if a system is at rest, its components are subject to this force. We can think of a tension in a given rope as T = (m × g) + (m × a), where "g" is the acceleration due to gravity of any objects the rope is supporting and "a" is any other acceleration on any objects the rope is supporting.[2]

For the purposes of most physics problems, we assume ideal strings - in other words, that our rope, cable, etc. is thin, massless, and can't be stretched or broken.

As an example, let's consider a system where a weight hangs from a wooden beam via a single rope (see picture). Neither the weight nor the rope are moving - the entire system is at rest. Because of this, we know that, for the weight to be held in equilibrium, the tension force must equal the force of gravity on the weight. In other words, Tension (Ft) = Force of gravity (Fg) = m × g.

Assuming a 10 kg weight, then, the tension force is 10 kg × 9.8 m/s2 = 98 Newtons.

7 0
3 years ago
The head of a rattlesnake can accelerate at 49 m/s2 in striking a victim. If a car could do as well, how long would it take to r
Anettt [7]
<h2>Time taken is 0.459 seconds</h2>

Explanation:

We have equation of motion v = u + at

     Initial velocity, u = 0 m/s

     Final velocity, v = 81 km/hr = 22.5 m/s    

     Time, t = ?

     Acceleration, a = 49 m/s²

     Substituting

                      v = u + at  

                      22.5 = 0 + 49 x t

                      t = 0.459 seconds

   Time taken is 0.459 seconds

3 0
3 years ago
3. A typical 12-V car battery can deliver about 750,000 C of charge before dying. This is not a lot of charge. As a comparison,
love history [14]

Answer:

Explanation:

Energy = volt x charge

= 12 x 750000 J

= 9000,000 J

Latent heat of vaporisation

= 2260000 J / kg

kg of water vaporised

= 9000,000 / 2260000

= 3.982 kg .

3 0
3 years ago
If voltage , V = 100 + 6 volt and current , I = 10+ 0.2 A , then find <br> percentage error in R.
Akimi4 [234]

Explanation:

As we know, resistance is the ratio of voltage used and current flowing through the circuit. So,

<h3>R = V/I</h3>

By error calculation

<h3>∆R/R = [(∆V/V)100] + [(∆I/I)100]</h3>

V = 100 ± 6% V

I = 10 ± 0.2% A

∆R/R= (5/100)×100 + (0.2/10)×100

∆R/R=5+2=7%

<h2>So, percentage error in resistance (R) = ± 7%.</h2>
8 0
2 years ago
Other questions:
  • A compressed spring has elastic potential energy. Please select the best answer from the choices provided T F
    6·1 answer
  • The force involves the attraction between objects with mass. Strong nuclear. Gravitational. Electromagnetic. Weak nuclear
    6·2 answers
  • A force of 334 N has a work on an object of 823 J, what is the displacement that was made
    14·1 answer
  • What career has to do with fossil fuels??
    11·1 answer
  • (TIMED) Anyone know the answer to this question?
    7·2 answers
  • An ideal monatomic gas at temperature T is held in a container. If the gas is compressed isothermally, that is at constant tempe
    8·1 answer
  • An electric field of 6.1x 10^5 N/C is directed along a charge 2.9 x 10^-19 C. What
    14·1 answer
  • A wire of resistance R is cut into ten equal parts which are then connected in parallel. The equivalent resistance of the combin
    11·1 answer
  • Heat is added to a substance, but its temperature does not rise. Which one of the following statements provides the best explana
    8·2 answers
  • Compare and contrast the solar eclipse seen in this video to a lunar eclipse.
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!