In all chemical reactions, __________ and ____________ must be conserved. energy, matter atoms, heat enthalpy, energy

the car starts from a stop to travel 1100 meters in 14 seconds. it is clocked at 65 m/s at point k. find its average speed and a

inysia [295]

Answer:

The average velocity of the car is, V = 74.04 m/s

Explanation:

Given data,

The initial velocity of the car, u = 0 m/s

The displacement of the ca, S = 1100 m

The time period of travel, t = 14 s

The velocity of the car at point k, v = 65 m/s

Using the II equation of motion,

S = ut + ½ at²

Substituting the given values,

1100 = 0 + ½ x a x 14²

a = 11.22 m/s²

Using the III equation of motion

v² = u² + 2 as

v = √(2as) (∵ u = 0)

Substituting,

v = √(2 x 11.22 x 1100)

= 157.11 m/s

The average speed of the car,

$V=\frac{0+65+157.11}{3}$

V = 74.04 m/s

Hence, the average velocity of the car is, V = 74.04 m/s

4 0

2 years ago

You pull straight up on the string of a yo-yo with a force 0.35 N, and while your hand is moving up a distance 0.16 m, the yo-yo

jarptica [38.1K]

Answer:

a) 0.138J

b) 3.58m/S

c) (1.52J)(I)

Explanation:

a) to find the increase in the translational kinetic energy you can use the relation

$\Delta E_k=W=W_g-W_p$

where Wp is the work done by the person and Wg is the work done by the gravitational force

By replacing Wp=Fh1 and Wg=mgh2, being h1 the distance of the motion of the hand and h2 the distance of the yo-yo, m is the mass of the yo-yo, then you obtain:

$Wp=(0.35N)(0.16m)=0.056J\\\\Wg=(0.062kg)(9.8\frac{m}{s^2})(0.32m)=0.19J\\\\\Delta E_k=W=0.19J-0.056J=0.138J$

the change in the translational kinetic energy is 0.138J

b) the new speed of the yo-yo is obtained by using the previous result and the formula for the kinetic energy of an object:

$\Delta E_k=\frac{1}{2}mv_f^2-\frac{1}{2}mv_o^2$

where vf is the final speed, vo is the initial speed. By doing vf the subject of the formula and replacing you get:

$v_f=\sqrt{\frac{2}{m}}\sqrt{\Delta E_k+(1/2)mv_o^2}\\\\v_f=\sqrt{\frac{2}{0.062kg}}\sqrt{0.138J+1/2(0.062kg)(2.9m/s)^2}=3.58\frac{m}{s}$

the new speed is 3.58m/s

c) in this case what you can compute is the quotient between the initial rotational energy and the final rotational energy

$\frac{E_{fr}}{E_{fr}}=\frac{1/2I\omega_f^2}{1/2I\omega_o^2}=\frac{\omega_f^2}{\omega_o^2}\\\\\omega_f=\frac{v_f}{r}\\\\\omega_o=\frac{v_o}{r}\\\\\frac{E_{fr}}{E_{fr}}=\frac{v_f^2}{v_o^2}=\frac{(3.58m/s)}{(2.9m/s)^2}=1.52J$

hence, the change in Er is about 1.52J times the initial rotational energy

5 0

2 years ago

Read 2 more answers

How does the speed of visible light compare with the speed of gamma rays

DochEvi [55]

Answer:

They are the same

Explanation:

Electromagnetic waves consist of perpendicular oscillations of electric and magnetic field, which oscillate perpendicularly to the direction of motion of the wave (transverse wave). One property of the electromagnetic waves is that they travel in a vacuum always at the same speed, called speed of light:

$c=3.0\cdot 10^8 m/s$

Electromagnetic waves are classified into 7 different types according to their frequency; from highest to lowest frequency, we have:

Gamma rays

X-rays

Ultraviolet

Visible light

Infrared

Microwaves

Radio waves

We see that both visible light and gamma rays are electromagnetic waves, so they both travel in a vacuum at the same speed, the speed of light.

3 0

3 years ago

How do you describes a mixture

yanalaym [24]

Answer:

A mixture is a combination of two or more substances in which the identities of substances are retained. ... The mixture can be in the form of solutions, colloids and suspension. The mixture will have characteristics different from the parent material due to the combination of different kinds of materials.

Hope this helps!!!

3 0

2 years ago

Read 2 more answers

W=4j, d=2m,and F=10N find cosine

ruslelena [56]

Correct your answer to the amount of significant figures the questions wants

4 0

2 years ago