Physics, 07.01.2020 21:31 clonetrooper099

An archer puts a 0.30 kg arrow to the bowstring. an average force of 201 n is exerted to draw the string back 1.3 m.
a. assuming no frictional loss, with what speed does the arrow leave the bow?
b. if the arrow is shot straight up, how high does it rise?

Answers: 2

Show answers

Answers

Answer from: ballin4534

a. The arrow leaves the bow at 30 m/s.

b. The maximum height of the arrow is 46 m.

Explanation:

Hi there!

a. As the string is being stretched the arrow acquires elastic potential energy and when it is released, all the elastic potential energy of the arrow will be transformed into kinetic energy (since no energy is dissipated by friction). Then, the initial elastic potential energy (EPE) of the arrow is equal to its final kinetic energy (KE):

EPE = KE

1/2 · k · x² = 1/2 · m · v²

Where:

k = spring constant.

x = stretching distance of the string.

m = mass of the arrow.

v = speed.

The spring constant can be calculated using Hooke´s law (the force needed to stretch or compress a spring is proportional to the stretching or compressing distance (i.e: the more you compress or stretch the spring, the more force you need to apply)):

Mathematically, it is expressed as follows:

F = kx

F/x = k

Then, replacing k in the equation:

1/2 · k · x² = 1/2 · m · v²

1/2 · F/x · x² = 1/2 · m · v²

1/2 · F · x = 1/2 · m · v²

Solving for v:

F · x / m = v²

v = √(F · x / m)

v = √ (201 N · 1.3 m / 0.30 kg)

v = 30 m/s

The arrow leaves the bow at 30 m/s

b. If the arrow is shot straight up, the initial kinetic energy (or elastic potential energy) will be converted into gravitational potential energy. At the maximum height, the kinetic energy of the arrow is zero (v = 0, KE = 0) meaning that all the initial kinetic energy of the arrow was converted into gravitational potential energy (PE). Then, the final potential energy has to be equal to the initial kinetic energy because the total energy is conserved (i.e. it remains constant).

PE = KE

m · g · h = 1/2 · m · v²

Where:

g = acceleration due to gravity (9.8 m/s²)

h = height.

Solving for h:

h = 1/2 · v²/g

h = 1/2 · (30 m/s)² / 9.8 m/s²

h = 46 m (44 m without rounding the velocity).

The maximum height of the arrow is 46 m.

Answer from: Quest

Idon't know it i just need my points lol

Answer from: Quest

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is

answer

1,500

kg • m/s.

Another question on Physics

Physics, 22.06.2019 05:00

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

Answers: 3

Answer

Physics, 22.06.2019 14:20

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.

Answers: 1

Answer

Physics, 22.06.2019 18:40

Which body is in equilibrium? (1) a satellite orbiting earth in a circular orbit (2) a ball falling freely toward the surface of earth (3) a car moving with a constant speed along a straight, level road (4) a projectile at the highest point in its trajectory

Answers: 2

Answer

Physics, 22.06.2019 19:50

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.

Answers: 3

Answer

You know the right answer?

An archer puts a 0.30 kg arrow to the bowstring. an average force of 201 n is exerted to draw the st...

Questions