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
marshall27 [118]
1 year ago
15

a0.155 kg arrow is shot from ground level, upward at 31.4 m/s. what is its kinetic energy (ke) when it is 30.0 m above the groun

d ?
Physics
1 answer:
swat321 year ago
5 0

The kinetic energy (KE) of a 0.155 kg arrow that is shot from ground level, upward at 31.4 m/s, when it is 30.0 m above the ground is 30.85 J

Assuming air friction is negligible,

a = - 9.8 m / s²

u = 31.4 m / s

s = 30 m

v² = u² + 2 a s

v² = 31.4² + ( 2 * - 9.8 * 30 )

v² = 985.96 - 588

v² = 397.96 m / s

KE = 1 / 2 m v²

KE = 1 / 2 * 0.155 * 397.96

KE = 0.0775 * 397.96

KE = 30.85 J

Therefore, the kinetic energy ( KE ) when it is 30.0 m above the ground is 30.85 J

To know more about kinetic energy

brainly.com/question/24360064

#SPJ1

You might be interested in
As a laudably skeptical physics student, you want to test Coulomb's law. For this purpose, you set up a measurement in which a p
kherson [118]

Explanation:

The Coulomb's law states that the magnitude of each of the electric forces between two point-at-rest charges is directly proportional to the product of the magnitude of both charges and inversely proportional to the square of the distance that separates them:

F=\frac{kq_1q_2}{d^2}

In this case we have an electron (-e) and a proton (e), so:

F=-\frac{ke^2}{d^2}\\F=-\frac{8.99*10^9\frac{N\cdot m^2}{s^2}(1.6*10^{-19}C)^2}{(933*10^{-9}m)^2}\\F=-2.64*10^{-16}N

In this case, the electric force is negative, therefore, the force is repulsive and its magnitude is:

F=2.64*10^{-16}N

3 0
3 years ago
A current of 9 A flows through an electric device with a resistance of 43 Ω. What must be the applied voltage in this particular
lubasha [3.4K]

Voltage, V = IR

Where I is current in Ampere, R is Resistance in Ohms.

V = 9A * 43 Ω

V = 387 V

8 0
3 years ago
A runner starts from rest and in 3 s reaches a speed of 8 m/s. If we assume that the speed changed at a constant rate (constant
Stells [14]

Answer:

The average speed of the runner is 4 m/s.

Explanation:

Hi there!

The average speed (a.s) is calculated by dividing the traveled distance (d) over the time needed to travel that distance (t):

a.s = d / t

So, let´s find the distance traveled in those 3 s. For that, we can use the equation of position of an object moving in a straight line with constant acceleration:

x = x0 + v0 · t + 1/2 · a · t²

Where:

x = position of the object at time t.

x0 = initial position.

v0 = initial velocity.

t = time.

a = acceleration.

If we place the origin of the frame of reference at the point where the runner starts, then, x0 = 0. Since the runner starts from rest, v0 = 0. So, the equation gets reduced to this:

x = 1/2 · a · t²

We have the time (3 s), so let´s find the acceleration. For that, we can use the equation of velocity of an object moving in a straight line with constant acceleration:

v = v0 + a · t

Where "v" is the velocity at a time "t". Since v0 = 0, then:

v = a · t

At t = 3 s, v = 8 m/s

8 m/s = a · 3 s

8/3 m/s² = a

So let´s find the position of the runner at t = 3 s (In this case, the position of the runner will be equal to the traveled distance):

x = 1/2 · a · t²

x = 1/2 · 8/3 m/s² · (3 s)²

x = 12 m

Now, we can calcualte the average speed:

a.s = d/t

a.s = 12 m / 3 s

a.s = 4 m/s

The average speed of the runner is 4 m/s.

4 0
3 years ago
Help, please
Mice21 [21]

Answer:

A and A

Explanation:

see paper for work! :)

8 0
2 years ago
While the change in blank will remain the same during a collision, the force needed to bring an object to a stop can be blank if
Ahat [919]

Explanation :

There are two types of collision i.e. elastic and elastic collision.

  • Elastic collision : In this type of collision, the total momentum and the kinetic energy of the particles remains constant.
  • Inelastic collision : In this type of collision, only the momentum remains constant while there is some loss of kinetic energy occurs.

From Newton's second law,

F = m a

a is the rate of change of velocity.

F=m\dfrac{v}{t}

There is a inverse relation between the force and the time of collision.

The change in <em><u>momentum</u></em> will remain the same during a collision, the force needed to bring an object to a stop can be <em><u>increased</u></em> if the time of the collision is <u><em>decreased</em></u>.

6 0
2 years ago
Read 2 more answers
Other questions:
  • Two spherical drops of mercury each have a charge of 0.10 nC and a potential of 300 V at the surface. The two drops merge to for
    7·1 answer
  • A hockey puck on a frozen pond is given an initial speed of 20.0 m/s. If the puck always remains on the ice and slides 115 m bef
    10·1 answer
  • a student uses a simple machine to help lift a load.when 40N of input force is applied to the machine it is able to lift 160N .w
    10·1 answer
  • Why does increasing the number trials increase confidence in the results of the experiment?
    9·2 answers
  • A wave which needs a medium (solid, liquid, gas) in order to propagate itself.
    8·2 answers
  • Refraction:
    13·1 answer
  • Andy took a bus and then walked from his home to downtown.
    14·1 answer
  • Based on the information in the table, which mineral is LEAST likely to be found in Earths rocks
    11·1 answer
  • I'm spending 98 points please help!
    6·2 answers
  • Which of the following statements about the
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!