Ask question

Ask question

All categories

3 years ago

12

A man jogs at a velocity of 2.5 m/s west for 1,200 s. He then walks at a velocity 1.0 m/s east for 500 s and then stops to rest

. What is the displacement of man when he stops to rest?

1 answer:

olganol [36]3 years ago

5 0

Speed of man towards West =2.5 m/s

Time to travel in the given direction = 1200 s

Total displacement towards west

$d_1 = v_1 t$

$d_1 = 2.5 \times 1200 = 3000 m$

Now speed of man towards East = 1 m/s

time to travel in east direction = 500 s

total displacement towards East

$d_2 = v_2 t$

$d_2 = 1 \times 500 = 500 m$

Now total displacement will be

$d = d_1 - d_2$

$d = 3000 - 500 = 2500 m$

so it is 2500 m towards west

You might be interested in

An object is placed 10 cm in front of a diverging mirror. What is the focal length of the mirror if the image appears 2 cm behin

Dafna1 [17]

Answer:

the focal length of the mirror is : $f=-2.5\,\,cm$

Explanation:

Use the formula for the formation of image using a divergent mirror and recalling that the image (s') that this mirror formed is virtual, so it is entered as a negative number in the formula. Use the object position (s) as 10, the image position (s') as -2, and derive the value of the focal length:

$\frac{1}{s} +\frac{1}{s'}=\frac{1}{f}\\\frac{1}{10} +\frac{1}{-2}=\frac{1}{f}\\\frac{1}{10} -\frac{1}{2}=\frac{1}{f}\\\frac{10\,f}{10} -\frac{10\,f}{2}=\frac{10\,f}{f}\\f-5\,f=10\\-4\,f=10\\f=-2.5\,\,cm$

6 0

3 years ago

A meter stick is held vertically with one end on the floor and is then allowed to fall. Find the speed of the other end when it

Tems11 [23]

Answer:

5.4 ms⁻¹

Explanation:

Here we have to use conservation of energy. Initially when the stick is held vertical, its center of mass is at some height above the ground, hence the stick has some gravitational potential energy. As the stick is allowed to fall, its rotates about one. gravitational potential energy of the stick gets converted into rotational kinetic energy.

$L$ = length of the meter stick = 1 m

$m$ = mass of the meter stick

$w$ = angular speed of the meter stick as it hits the floor

$v$ = speed of the other end of the stick

we know that, linear speed and angular speed are related as

$v = r w\\w = \frac{v}{r}$

$h$ = height of center of mass of meter stick above the floor = $\frac{L}{2} = \frac{1}{2} = 0.5 m$

$I$ = Moment of inertia of the stick about one end

For a stick, momentof inertia about one end has the formula as

$I = \frac{mL^{2} }{3}$

Using conservation of energy

Rotational kinetic energy of the stick = gravitational potential energy

$(0.5) I w^{2} = mgh\\(0.5)(\frac{mL^{2} }{3}) (\frac{v}{L} )^{2} = mgh\\(0.5)(\frac{v^{2} }{3}) = gh\\(0.5)(\frac{v^{2} }{3}) = (9.8)(0.5)\\v = 5.4 ms^{-1}$

7 0

3 years ago

At 20°c, the resistance of a sample of nickel is 525 ohms. what is the resistance when the sample is heated to 70°C?

Ipatiy [6.2K]

The resistance of the sample is $682.5\Omega$

Explanation:

The relationship between resistance of a material and temperature is given by the equation

$R(T)=R_0(1+\alpha (T-T_0))$

where

$R_0$ is the resistance at the temperature $T_0$

$\alpha$ is the temperature coefficient of resistance

For the sample of nickel in this problem, we have:

$R_0 = 525 \Omega$ when the temperature is $T_0 = 20^{\circ}C$

While the temperature coefficient of resistance of nickel is

$\alpha = 0.006/^{\circ}C$

Therefore, the resistance of the sample when its temperature is

$T=70^{\circ}C$

is

$R=(525)(1+0.006(70-20))=682.5 \Omega$

Learn more about resistance:

brainly.com/question/4438943

brainly.com/question/10597501

brainly.com/question/12246020

#LearnwithBrainly

3 0

3 years ago

1. Who first published the classification of the elements that is the basis of our periodic table today?

Gre4nikov [31]

That particular group of elements is reffered to as the "Noble Gasses"--a title that comes from the fact that these gases are very "secure" and don't mix well with other elements.

4 0

3 years ago

If the pressure exerted by the liquid of density 500kg/m3 is 20,000Pa. What is height of liquid column.

gregori [183]

The height of the liquid column is 4.08 metres.

4 0

2 years ago