How would i solve these problems, nobody in my class understands and there is a substitute

A boy is playing with a ball of mass 72g attached to a string. He is moving it at constant speed in a horizontal circle of radiu

irina [24]

Answer:

Explanation:

radius of circle r = 0.9 m.

(a ) In a motion on circular path , work done is zero because force ( centripetal force ) acts perpendicular to displacement .

( b )

Tension in string T = m ω²r

Putting the values

60 = .072 x ω² x 0.9

ω² = 926

ω = 30.4 rad /s

angle made in 20 revolutions θ = 20 x 2π = 126.6 rad

time taken = θ / ω

= 126.6 / 30.4

= 4.16 s .

3 0

3 years ago

8892 ml to grams then to mg

andrew11 [14]

Answer:

8892 ml = 8892 gm = 8892000 mg

1 ml = 1 gram

8892 ml = 8892 gram

1 gram or ml = 1000 milligram

8892 ml = 8892 × 1000 = 8892000 milligram

hope this helps

have a good day :)

Explanation:

remember: 1 kilogram = 1000 gram = 1000000 milligram.

Milliliter is expressed same as gram and liter is expressed same as kilogram.

1 meter = 100 cm, 1 kilometer = 1000 meter,

1 cm = 10 millimeter.

7 0

2 years ago

Read 2 more answers

What is the acceleration of an object that goes from 45m/s to 10 m/s in 5 seconds?

kipiarov [429]

Answer:

$\boxed {\boxed {\sf a= -7 \ m/s^2}}$

Explanation:

Acceleration is the change in velocity over time.

$a= \frac {v_f-v_i}{t}$

The object accelerates <em>from</em> 45 meters per second <em>to </em>10 meters per second in 5 seconds. Therefore,

$v_f=10 \ m/s \\v_i= 45 \ m/s \\t= 5 \ s$

Substitute the values into the formula.

$a= \frac{ 10 \ m/s - 45 \ m/s}{5 \ s}$

Solve the numerator.

$a= \frac { -35 \ m/s}{5 \ s}$

Divide.

$a= -7 \ m/s/s$

$a= -7 \ m/s^2$

The acceleration of the object is -7 meters per square second. The acceleration is negative because the object's velocity decreases and the object slows down.

5 0

3 years ago

oscillating spring mass systems can be used to experimentally determine an unknown mass without using a mass balance. a student

12345 [234]

Answer:

Mass, m = 6.18 kg

Explanation:

Given the following data;

Frequency, F = 10 Hz

Spring constant, k = 250 N/m

We know that pie, π = 22/7

To find the mass, we would use the following formula;

F = 1/2π√(k/m)

Where;

F is the frequency of oscillation.

k is the spring constant.

m is the mass of the spring.

Substituting into the formula, we have;

10 = 1/2 * 22/7 * √250/m

10 = 22/14 * √250/m

Cross-multiplying, we have;

140 = 22 * √250/m

Dividing both sides by 22, we have;

140/22 = √250/m

6.36 = √250/m

Taking the square of both sides, we have;

6.36² = (√250/m)²

40.45 = 250/m

Cross-multiplying, we have;

40.45m = 250

Mass, m = 250/40.45

Mass, m = 6.18 kg

3 0

2 years ago

A water wheel rotates with a period of 2.26 s. If the water wheel has a radius of l.94 m,

Dafna11 [192]

Answer:

The correct answer is B)

Explanation:

When a wheel rotates without sliding, the straight-line distance covered by the wheel's center-of-mass is exactly equal to the rotational distance covered by a point on the edge of the wheel. So given that the distances and times are same, the translational speed of the center of the wheel amounts to or becomes the same as the rotational speed of a point on the edge of the wheel.

The formula for calculating the velocity of a point on the edge of the wheel is given as

$V_{r}$ = 2π r / T

Where

π is Pi which mathematically is approximately 3.14159

T is period of time

Vr is Velocity of the point on the edge of the wheel

The answer is left in Meters/Seconds so we will work with our information as is given in the question.

Vr = (2 x 3.14159 x 1.94m)/2.26

Vr = 12.1893692/2.26

Vr = 5.39352619469

Which is approximately 5.39

Cheers!

7 0

2 years ago