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3 years ago

A book is on the table. If the weight of the book is 25 newtons, what is the magnitude and direction of the normal force?

Physics

2 answers:

Andrej [43]3 years ago

4 0

I'm not sure about the magnitude, but the direction of the normal force is upward.

bulgar [2K]3 years ago

3 0

Magnitude : 25 N

Direction: upward

Explanation:

The weight of the book is 25 N and is directed downward: this is the force exerted by the book on the table.

As stated in Newton's third law, for every object A that exerts a force on an object B, object B exerts an equal and opposite force on object A.

In this case, object A is the book and object B is the table. Based on Newton's third law, we can say that the table exerts an equal and opposite force on the book: therefore, the magnitude of the normal force is equal to the weight of the book (25 N), while the direction is opposite (so, upward).

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The blade of a windshield wiper moves through an angle of 90.08 in 0.40 s. The tip of the blade moves on the arc of a circle tha

oksian1 [2.3K]

Answer:

The centripetal acceleration is 6.95 m/s²

Explanation:

Given;

angular displacement of the blade, θ = 90.08⁰

duration of motion of the blade, t = 0.4 s

radius of the circle moved by the blade, r = 0.45 m

The angular speed of the blade in radian is calculated as;

$\omega = \frac{\theta}{t} \times \frac{\pi \ radian}{180^0} \\\\\omega = \frac{90.08 ^0}{0.4 \ s} \times \frac{\pi \ radian}{180^0} \\\\\omega = 3.93 \ rad/s$

The centripetal acceleration is calculated as;

a = ω²r

a = (3.93)² x 0.45

a = 6.95 m/s²

7 0

3 years ago

Given two vectors A--> = 4.20 i^+ 7.20 j^ and B--> = 5.70 i^− 2.40 j^ , find the scalar product of the two vectors A-->

Arisa [49]

Answer:

$\vec{A}\times \vec{B}=-51.12\hat{k}$

$\theta=83.2^{\circ}$

Explanation:

We are given that

$\vec{A}=4.2\hat{i}+7.2\hat{j}$

$\vec{B}=5.70\hat{i}-2.40\hat{j}$

We have to find the scalar product and the angle between these two vectors

$\vec{A}\times \vec{B}=\begin{vmatrix}i&j&k\\4.2&7.2&0\\5.7&-2.4&0\end{vmatrix}$

$\vec{A}\times \vec{B}=\hat{k}(-10.08-41.04)=-51.12\hatk}$ $\hat{k}$

Angle between two vectors is given by

$sin\theta=\frac{\mid a\times b\mid}{\mid a\mid \mi b\mid}$

Where $\theta$ in degrees

$\mid{\vec{A}}\mid=\sqrt{(4.2)^2+(7.2)^2}=8.3$

Using formula $\mid a\mid=\sqrt{x^2+y^2}$

Where x= Coefficient of unit vector i

y=Coefficient of unit vector j

$\mid{\vec{B}}\mid=\sqrt{5.7)^2+(-2.4)^2}=6.2$

$\mid{\vec{A}\times \vec{B}}\mid=\sqrt{(-51.12)^2}=51.12$

Using the formula

$sin\theta=\frac{51.12}{8.3\times 6.2}=0.993$

$\theta=sin^{-1}(0.993)=83.2$ degrees

Hence, the angle between given two vectors= $83.2^{\circ}$

7 0

4 years ago

You punt a ball straight up at 20 m/s. What is the balls hangtime

Natalija [7]

The hang time of the ball is 4.08 s

Explanation:

The ball is in free fall motion: this means that it is acted upon gravity only, so its acceleration is the acceleration of gravity,

$a=g=-9.8 m/s^2$

downward (the negative sign refers to the downward direction).

Since this is a uniformly accelerated motion, we can solve the problem by using the following suvat equation:

$v=u+at$

where

v is the final velocity

u is the initial velocity

a is the acceleration

t is the time

First we calculate the time it takes for the ball to reach the maximum height, where the velocity is zero:

v = 0

Substituting:

u = +20 m/s

$a=-9.8 m/s^2$

we find t

$t=\frac{v-u}{a}=\frac{0-20}{-9.8}=2.04 s$

The motion of the ball is symmetrical, so the total time of flight is just twice the time needed to reach the maximum height, therefore:

$T=2t=2(2.04)=4.08 s$

Learn more about free fall:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

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#LearnwithBrainly

4 0

3 years ago

A child pulls on a wagon with a force of 75 N. If the wagon moves a total of 42 m in 3.1 min, what is the average power delivere

exis [7]

Answer:

16.96 W

Explanation:

Power: This can be defined as the rate at which work is done by an object. The S.I unit of power is Watt(W).

From the question,

P = (F×d)/t....................... Equation 1

Where P = power, F = force, d = distance, t = time.

Given: F = 75 N, d = 42 m, t = 3.1 min = 3.1×60 = 186 s

Substitute these values into equation 1

P = (75×42)/186

P = 16.94 W

Hence the average power delivered by the child = 16.96 W

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3 years ago

A pool and stops at the

Bas_tet [7]

In Linear motion the swimmer swims

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3 years ago