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
Margaret [11]
3 years ago
6

A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 19.0 m/s when the

hand is 2.50 m above the ground.
Required:
How long is the ball in the air before it hits the ground?
Physics
1 answer:
german3 years ago
5 0

Answer: 4 s

Explanation:

Given

The ball leaves the hand of student with a speed of u=19\ m/s

When the hand is h=2.5\ m above the ground

Using the equation of motion we can write

h=ut+\dfrac{1}{2}at^2

Substitute the values

\Rightarrow 2.5=-19t+0.5\times 9.8t^2\\\Rightarrow 4.9t^2-19t-2.5=0\\\\\Rightarrow t=\dfrac{19\pm \sqrt{(-19)^2-4\times 4.9\times (-2.5)}}{2\times 19}\\\Rightarrow t=4.0049\quad [\text{Neglecting the negative value of }t]

Thus, the ball will take 4 s to hit the ground.

You might be interested in
Which of the following statements about the Coriolis effect is correct?
labwork [276]

Answer:

Option D

The Coriolis effect works at right angles to the direction of airflow

Explanation:

At the equator, Coriolis effect is negligible, basically zero while it's strongest at the poles (to imply statement B is wrong). Moreover, Coriolis effect is affected by the speed of wind and it also affects the speed of wind since when the wind speed decreases, due to friction for example, the Coriolis effect is also reduces.

7 0
3 years ago
A parachutist falls 50.0 m without friction. When the parachute opens, he slows down at a rate of 67 m/s*2. If he reaches the gr
KIM [24]

Answer:

3.49 seconds

3.75 seconds

-43200 ft/s²

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

s=ut+\frac{1}{2}at^2\\\Rightarrow 50=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{50\times 2}{9.81}}\\\Rightarrow t=3.19\ s

Time the parachutist falls without friction is 3.19 seconds

v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 50+0^2}\\\Rightarrow v=31.32\ m/s

Speed of the parachutist when he opens the parachute 31.32 m/s. Now, this will be considered as the initial velocity

v=u+at\\\Rightarrow 11=31.32+9.81t\\\Rightarrow t=\frac{11-31.32}{-67}=0.3\ s

So, time the parachutist stayed in the air was 3.19+0.3 = 3.49 seconds

s=ut+\frac{1}{2}at^2\\\Rightarrow \frac{s}{2}=0t+\frac{1}{2}\times a\times t^2\\\Rightarrow \frac{s}{2}=\frac{1}{2}at^2

s=ut+\frac{1}{2}at^2\\\Rightarrow \frac{s}{2}=u1.1+\frac{1}{2}\times a\times 1.1^2

Now the initial velocity of the last half height will be the final velocity of the first half height.

v=u+at\\\Rightarrow v=at

Since the height are equal

\frac{1}{2}at^2=u1.1+\frac{1}{2}\times a\times 1.1^2\\\Rightarrow \frac{1}{2}at^2=at1.1+\frac{1}{2}\times a\times 1.1^2\\\Rightarrow 0.5t^2-1.1t-0.605=0\\\Rightarrow 500t^2-1100t-605=0

t=\frac{11\left(1+\sqrt{2}\right)}{10},\:t=\frac{11\left(1-\sqrt{2}\right)}{10}\\\Rightarrow t=2.65, -0.45

Time taken to fall the first half is 2.65 seconds

Total time taken to fall is 2.65+1.1 = 3.75 seconds.

When an object is thrown with a velocity upwards then the velocity of the object at the point to where it was thrown becomes equal to the initial velocity.

v^2-u^2=2as\\\Rightarrow a=\frac{v^2-u^2}{2s}\\\Rightarrow a=\frac{0^2-240^2}{2\times \frac{8}{12}}\\\Rightarrow a=-43200\ ft/s^2

Magnitude of acceleration is -43200 ft/s²

5 0
3 years ago
Am i correct? If not then which one
cupoosta [38]

Answer:

Yes, it's correct

Explanation:

Newton's second Law states that the acceleration of an object is proportional to the net force applied on it, according to the equation:

F=ma

where

F is the net force on the object

m is the mass of the object

a is the acceleration of the object

We can re-arrange the previous equation in order to solve explicitely for a, the acceleration, and we find:

F=ma\\\frac{F}{m}=\frac{ma}{m}\\\frac{F}{m}=a\\a=\frac{F}{m}

So, we see that the acceleration is proportional to the net force and inversely proportional to the mass of the object.

4 0
3 years ago
i will give brainliest Which of the following structures are present in plant cells but absent in animal cells? Choose 1 answer:
Sonja [21]

Answer:

A. cell walls

Explanation:

Plants have cell walls but animals dont.

3 0
4 years ago
Which of the following is the flow of electrons through a wire or a conductor
Hatshy [7]
Wires or silver and copper
8 0
3 years ago
Other questions:
  • How much heat is released to freeze 47.30 grams of copper at its freezing point of 1,085°C? The latent heat of fusion of copper
    6·2 answers
  • Which of these temperatures is closest to 100 k?
    5·1 answer
  • Ultraviolent radiation is one of many types of energy that comes to Earth from the Sun.
    15·2 answers
  • If the color red has a wavelength of 7.0 107 m. its frequency is
    12·2 answers
  • How many valence electrons are transferred from the calcium atom to iodine in the formation of the compound calcium iodide?
    15·1 answer
  • Anatomy and Phys PLEASE HELP
    12·2 answers
  • To what does the amplitude of a sound refer to?
    12·1 answer
  • Walk done in units time is called​
    14·1 answer
  • 1. A person walks 50 meters north, and then travels 150 meters to the south. What is the total distance they travelled? What is
    12·1 answer
  • A model shows a machine that works using electric fields. What would this machine need for the electrical field to function prop
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!