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
Sveta_85 [38]
3 years ago
13

You and your friend Peter are putting new shingles on a roof pitched at 25 ∘ . You're sitting on the very top of the roof when P

eter, who is on the edge of the roof, 5.4 m away, asks you for the box of nails. Rather than carry the 2.4 kg box of nails down to Peter, you decide to give the box a push and have it slide down to him. Part A If the coefficient of kinetic friction between the box and the roof is 0.51, with what speed should you push the box to have it gently come to rest right at the edge of the roof?
Physics
1 answer:
Art [367]3 years ago
6 0

Answer:

Explanation:

Frictional force acting on the box = mg cos 25 x μ where μ is coefficient of friction

= 2.4 x 9.8 x cos 25 x .51 = 10.87 N

Weight of the box acting along the incline = mg sin 25 = 9.94 N

Net force = 10.87 - 9.94 = .93 N . It will create a deceleration of .93 / 2.4

= .3875 m /s² in the box.

v² = u² - 2 a s

v = 0 , a = .3875 , s = 5.4 m

= = u² - 2 x .3875 x 5.4

u = 2.045 m /s

You might be interested in
The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that
Arlecino [84]

Answer:

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are <u>due to water's partial charges.</u>

Explanation:

The partial negative charge on oxygen and partial positive charge on hydrogen enables them to make hydrogen bond and also makes it to dissolve the the other substances having partial charges.

4 0
3 years ago
A ball of mass 0.500 kg is carefully balanced on a shelf that is 2.70 m above the ground. What is its gravitational potential en
ratelena [41]

Answer:

The gravitational potential energy of the ball is 13.23 J.

Explanation:

Given;

mass of the ball, m = 0.5 kg

height of the shelf, h = 2.7 m

The gravitational potential energy is given by;

P.E = mgh

where;

m is mass of the ball

g is acceleration due to gravity = 9.8 m/s²

h is height of the ball

Substitute the givens and solve for gravitational potential energy;

PE = (0.5 x 9.8 x 2.7)

P.E = 13.23 J

Therefore, the gravitational potential energy of the ball is 13.23 J.

8 0
3 years ago
estion: Why is it important to use vector quantities and not just scalar quantities to describe the motion of an object? Vector
Vera_Pavlovna [14]

Answer:

Vector quantities are important in the study of motion. Some examples of vector quantities include force, velocity, acceleration, displacement, and momentum. The difference between a scalar and vector is that a vector quantity has a direction and a magnitude, while a scalar has only a magnitude. Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude. A quantity which does not depend on direction is called a scalar quantity. Vector quantities have two characteristics, a magnitude and a direction. The resulting motion of the aircraft in terms of displacement, velocity, and acceleration are also vector quantities. A vector quantity is different to a scalar quantity because a quantity that has magnitude but no particular direction is described as scalar. A quantity that has magnitude and acts in a particular direction is described as vector.

Explanation:

8 0
3 years ago
PLEASE HELP!!!!
defon

Answer:

v = 2.45 m/s

Explanation:

first we find the time taken during this motion by considering the vertical motion only and applying second equation of motion:

h = Vi t + (1/2)gt²

where,

h = height of cliff = 15 m

Vi = Initial Vertical Velocity = 0 m/s

t = time taken = ?

g = 9.8 m/s²

Therefore,

15 m = (0 m/s) t + (1/2)(9.8 m/s²)t²

t² = (15 m)/(4.9 m/s²)

t = √3.06 s²

t = 1.75 s

Now, we consider the horizontal motion. Since, we neglect air friction effects. Therefore, the horizontal motion has uniform velocity. Therefore,

s = vt

where,

s = horizontal distance covered = 4.3 m

v = original horizontal velocity = ?

Therefore,

4.3 m = v(1.75 s)

v = 4.3 m/1.75 s

<u>v = 2.45 m/s</u>

8 0
3 years ago
If a steady-state heat transfer rate of 3 kW is conducted through a section of insulating material 1.0 m2 in cross section and 2
kaheart [24]

Answer:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

So then the difference of temperature across the material would be \Delta T = 375 K

Explanation:

For this case we can use the Fourier Law of heat conduction given by the following equation:

Q = -kA \frac{\Delta T}{\Delta x}   (1)

Where k = thermal conductivity = 0.2 W/ mK

A= 1m^2 represent the cross sectional area

Q= 3KW represent the rate of heat transfer

\Delta T is the temperature of difference that we want to find

\Delta x=2.5 cm =0.025 m represent the thickness of the material

If we solve \Delta T in absolute value from the equation (1) we got:

\Delta T =\frac{Q \Delta x}{Ak}

First we convert 3KW to W and we got:

Q= 3 KW* \frac{1000W}{1 Kw}= 3000 W

And we have everything to replace and we got:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

So then the difference of temperature across the material would be \Delta T = 375 K

5 0
4 years ago
Other questions:
  • Who invented steam engine​
    13·2 answers
  • Calculate the heat energy needed to change the temperature of 2 kg of copper from 10°C to 110°C.
    14·2 answers
  • the gravitational force that earth exerts on the moon equals 2.03 x 10^20N. The moons mass is 7.35 x 10^22kg. What is the accele
    11·1 answer
  • A paper airplane with mass 0.1 kg is flying 1.5 m above the ground with a speed of 2 m/s. what is the total mechanical energy of
    15·1 answer
  • A baseball player throws a baseball with a velocity of 13 m/s north. It is caught by a second player seven seconds later. How fa
    7·1 answer
  • The sugar molecule known as sucrose is a polar molecule. Which statement BEST summarizes how sucrose will dissolve in water?
    13·1 answer
  • Electric force and magnetic force are the only forces that can both do what? *
    14·1 answer
  • Can you help and explain these for me?
    9·1 answer
  • 1. Through the law of gravity, Newton showed that two objects attracted by gravity actually orbit
    9·1 answer
  • Two planes fly in opposite directions. One travels 450 mi/h and the other flies 550 mi/h. How long will it take before they are
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!