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3 years ago

9

a measurement of 152.4 mm has 4 significant figures, because there are 4 digits. What about 152,400 mm? How many significant fig

ures do you think it has

1 answer:

den301095 [7]3 years ago

5 0

Answer:

Also 4.

Explanation:

If there was a decimal point after the last zero, you'd count the two zeroes as significant.

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An airplane, starting from rest, moves down the runway at constant acceleration for 18 s and then takes off at a speed of 60 m/s

ruslelena [56]

Answer:

a =3.33 m/s²

Explanation:

given,

initial speed of Plane, u = 0 m/s

final speed of plane, v = 60 m/s

time of the acceleration, t = 18 s

average acceleration of the plane, a = ?

average acceleration is equal to change in velocity per unit time.

$a = \dfrac{v - u}{t}$

$a = \dfrac{60 - 0}{18}$

$a = \dfrac{60}{18}$

a =3.33 m/s²

Hence, average acceleration of the plane is equal to a =3.33 m/s²

4 0

3 years ago

Read 2 more answers

An elevator is moving down with an acceleration of 3.36 m/s2.

sergeinik [125]

Answer : 413.44N

Here it is given that an elevator is moving down with an acceleration of 3.36 m/s² . And we are interested in finding out the apparent weight of a 64.2 kg man . For the diagram refer to the attachment .

From the elevator's frame ( non inertial frame of reference) , we would have to think of a pseudo force.
The direction of this force is opposite to the direction of acceleration the frame and its magnitude is equal to the product of mass of the concerned body with the acceleration of the frame .
When a elevator accelerates down , the weight recorded is less than the actual weight .

From the Free body diagram ,

$\sf\longrightarrow Weight = mg - ma \\$

$\sf\longrightarrow Weight = m ( g - a ) \\$

Mass of the man = 64.2 kg

$\sf\longrightarrow Weight = 64.2( 9.8 - 3.36) N\\$

$\sf\longrightarrow Weight = 64.2 * 6.44 N\\$

$\sf\longrightarrow \underline{\boxed{\bf Weight_{apparent}= 413.44 N }} \\$

5 0

2 years ago

The decomposition of ammonia to the elements is a first-order reaction with a half-life of 200 s at a certain temperature. How l

Feliz [49]

Based on the half-life of the reaction, time taken for the partial pressure of ammonia to decrease from 0.100 atm to 0.00625 atm is 800 seconds.

<h3>What is the half-life of a substance?</h3>

The half-life of a substance is the time taken for half the amount of atoms present in that substance to decay.

The half-life of the reaction is 200 seconds.

After, one half-life, pressure reduces to 0.0500 atm

After, two half-lives, pressure reduces to 0.0250 atm

After, three half-lives, pressure reduces to 0.01250 atm

After, four half-lives, pressure reduces to 0.00625 atm

Time taken = 4 * 200 = 800 seconds

Therefore, time taken for the partial pressure of ammonia to decrease from 0.100 atm to 0.00625 atm is 800 seconds.

Learn more about half-life at: brainly.com/question/26689704

#SPJ1

7 0

2 years ago

13. A proton moves at 7.50×107 m/s perpendicular to a magnetic field. The field causes the proton to travel in a circular path o

diamong [38]

The magnetic force acting on a charged particle moving perpendicular to the field is:

$F_{b}$ = qvB

$F_{b}$ is the magnetic force, q is the particle charge, v is the particle velocity, and B is the magnetic field strength.

The centripetal force acting on a particle moving in a circular path is:

$F_{c}$ = mv²/r

$F_{c}$ is the centripetal force, m is the mass, v is the particle velocity, and r is the radius of the circular path.

If the magnetic force is acting as the centripetal force, set $F_{b}$ equal to $F_{c}$ and solve for B:

qvB = mv²/r

B = mv/(qr)

Given values:

m = 1.67×10⁻²⁷kg (proton mass)

v = 7.50×10⁷m/s

q = 1.60×10⁻¹⁹C (proton charge)

r = 0.800m

Plug these values in and solve for B:

B = (1.67×10⁻²⁷)(7.50×10⁷)/(1.60×10⁻¹⁹×0.800)

B = 0.979T

5 0

4 years ago

If a 0.200-kilogram ball sits on a shelf 2.00 meters from the floor, how much mechanical energy (me) does it possess? More than

iogann1982 [59]

Answer:

Mechanical energy = 3.92 J

exactly 3.92 j

Explanation:

As we know that mechanical energy is sum of kinetic energy and potential energy of the system

so here we can say that mechanical energy is sum of kinetic energy of ball and its potential energy

Since ball is at rest so kinetic energy of the ball must be ZERO

Now for potential energy we know that

$U = mgh$

now we know

m = 0.2 kg

h = 2 m

now for potential ene'rgy

$U = (0.20)(9.8)(2)$

$U = 3.92 J$

so mechanical energy is given as

Mechanical Energy = 3.92 + 0 = 3.92 J

5 0

3 years ago