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3 years ago

a book is sitting still on your desk. are the forces acting on the book balanced or unbalanced? explain.

2 answers:

8 0

They are balanced. If the forces were not balanced the book would move*. In this example, the downward force of gravity on the book is counterbalanced by the upthrust of the desk.

fgiga [73]3 years ago

4 0

The answer to this is balanced. Remember the downward force of gravity on the book is counterbalanced by the upthrust of the desk. Note that moving objects can also have balanced forces acting on them. if an object is moving at a constant speed, the force acting on it are balanced. It they are unbalanced the object would either accelerate or decelerate.

Hope this helped.

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Find the distance traveled in one back-and-forth swing by the weight of a 12 in. Pendulum that swings through a 75 degree angle.

tia_tia [17]

The distance traveled by pendulum, in one back-and-forth swing is 75.75 inches.

The period of pendulum can be calculated by

$T = 2\pi \sqrt {\dfrac Lg}$

Where,

$T$ - period

$L$ - length = 12 inches

$g$ - gravitational acceleration = $\bold {9.8\rm \ m/s^2}$

Put the values,

$T = 2\pi \sqrt {\dfrac {12}{9.8}}\\\\T = 2 \times 3.14 \times \sqrt {0.122}\\\\T = 2.191$

Now, the angular displacement of the pendulum can be calculated by,

$\theta = A\times\rm \ cos(\omega T)$

Where,

$A$ - amplitude

$\theta$ - angle = $75^o$

$\omega$ - angular displacement = $2\pi/T$ = 2.866 m

Put the values and calculate for $\omega$ ,

$75 = A\times{\rm \ cos}(2.866\times 2.191)\\\\75 =A \times cos\ 6.26\\\\A =\dfrac {75}{0.99}\\\\A = 75.75 \rm \ inches$

Therefore, the distance traveled by pendulum, in one back-and-forth swing is 75.75 inches.

To know more about Amplitude of pendulum,

brainly.com/question/14840171

4 0

3 years ago

At a waterpark, sleds with riders are sent along a slippery, horizontal surface by the release of a large, compressed spring. Th

steposvetlana [31]

The sleds speed when the spring returns toits uncompressed length is v = 0.03 m/s.

Explanation:

Given,

force constant = 42 N/cm = 0.42 N/m, mass m = 68 kg, spring x = 0.39 m

The potential energy, U, stored in the spring is

U = 1/2 kx^2

= 1 / 2 $\times$ 0.42 $\times$ (0.39)^2

= 0.032 J

All its potential energy has been converted into kinetic energy since it has a uncompressed length.

K = 1/2 mv^2

v = sqrt (2K / m)

= √(( 2 $\times$ 0.032) / 68)

v = 0.03 m/s .

4 0

4 years ago

Kevin jumps straight up in the air to a height of 1 meter.At the top of his jump, he has potential energy of 1,000 joules.Answer

Llana [10]

Gravitational potential energy can be given by the equation
PE = mgh
where m is the mass,
g is the gravitational constant 9.81 or 10 depending on rounding
and h is the height

well weight is a force equiavlent to
W= m*g

so comparing that to the potential energy equation, divide the potential energy by the height and you will get weight in Newtons

3 0

3 years ago

The magnet below is cut in half. what will be the result?

loris [4]

Answer:

the correct would be c

Explanation:

a magnet will always have a north and a south so if you cut the magnet in half the north part would have a south on the opposite end and vice versa .

3 0

3 years ago

A and B start walking in the same direction at the same time around a circular park of diameter 4200 m. If A walks 10 m more tha

Liono4ka [1.6K]

Answer:

Va = 5000 m / 3600 s = 1.39 m/s

(Va - Vb) 60 = 10

Vb = Va - .167 = 1.22 m/s

(Va - Vb) T = 4200 Π where T is time for A to complete 1 more lap

.17 T = 4200 Π

T = 24700 Π time for A to again catch B

N = 1.39 * 24700 Answer:

Va = 5000 m / 3600 s = 1.39 m/s

(Va - Vb) 60 = 10

Vb = Va - .167 = 1.22 m/s

(Va - Vb) T = 4200 Π where T is time for A to complete 1 more lap

.17 T = 4200 Π

T = 24700 Π time for A to again catch B

N = 1.39 * 24700 Π / (4200 Π) = 8.2 laps

A will make 8 but not 9 rounds before catching B

6 0

2 years ago