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3 years ago

A mass m = 4.6 kg hangs on the end of a massless rope L = 2.16 m long. The pendulum is held horizontal and released from rest.

1 answer:

4 0

ind the velocity my using the conservation of energy mgh=1/2mv^2. At the bottom, the mass is turning in a circle with tension pointing up towards the center of the circle and weight pointing down. Use the centripetal force requirement mv^2/r=T-W and solve for T. Hope this helps.

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In each part calculate the kinetic energy of the given objects in joules a) an automobile whose mass is 1260kg moving at a speed

Contact [7]

Kinetic energy (KE) = 1/2 m v^2

Where:

m = mass = 1260 kg

v = speed = 66.3 km/h = 18.42 m/s

Replacing:

KE = 1/2 (1260 kg ) (18.42 m/s )^2 = 213,756.7 J

5 0

1 year ago

What dose it mean to say that mass is conserved during a physical change

Allushta [10]

Explanation:

When there is no change in chemical composition of a substance then it is known as physical change.

When we say that mass is conserved during a physical change then it means that total mass of the substance or object will remain the same from beginning till the end.

For example, a metal box of mass 20 grams is beaten with hammer. Its shape will change which is a physical change and after beaten with the hammer its mass still remains 20 grams.

6 0

3 years ago

Read 2 more answers

hree identical resistors are connected in series. When a certain potential difference is applied across the combination, the tot

pav-90 [236]

Answer:

The power dissipated if the three resistors were connected in parallel across the same potential difference is 405 W

Explanation:

Given;

three identical resistors connected in series

let the first resistor = R₁

let the second resistor = R₂

let the third resistor = R₃

Rt = R₁ + R₂ + R₃

Since the resistors are identical, thus, R₁ = R₂ = R₃ = R

Rt = 3R

Power is given as;

P = IV = V² / R

$P = \frac{V^2}{R_t} = \frac{V^2}{3R} \\\\3P = \frac{V^2}{R} ------equation(i)$

If the 3 identical resistor connection were changed to parallel, then the equivalent resistance in the circuit will be;

$\frac{1}{R_t} = \frac{1}{R_1} +\frac{1}{R_2} + \frac{1}{R_3} \\\\But, R_1 = R_2 = R_3\\\\\\frac{1}{R_t} = \frac{1}{R} +\frac{1}{R} + \frac{1}{R} \\\\\frac{1}{R_t} =\frac{3}{R} \\\\R_t = \frac{R}{3} \\\\P = \frac{V^2}{R_t} = \frac{3V^2}{R} \\\\P_{parallel} = \frac{3V^2}{R} ---------equation (ii)\\\\From \ equation \ (i), 3P_{series} = \frac{V^2}{R}, Substitute \ this \ into \ equation \ (ii)\\\\P = 3(\frac{V^2}{R} )\\\\P = 3(3P)\\\\P_{parallel} = 9P_{series}\\\\P_{parallel} = 9(45)\\\\$

$P_{parallel} = 405 \ W$

Therefore, the power dissipated if the three resistors were connected in parallel across the same potential difference is 405 W

4 0

3 years ago

A balloon contains helium with a mass of 0.00296 g. What is the volume of helium in the balloon? (Note: Helium’s density is 0.00

Over [174]

Answer:

178 cm3

Explanation:

From definition of density, it is mass per unit volume of an object, expressed as density=mass/volume and making volume the subject of the above formula we have volume= mass/density and substituting 0.00296 g for mass and 0.00001663 g/cm3 for density then we have

Volume=0.00296/0.00001663

Volume is approximately 178 cm3

7 0

3 years ago

A bus accelerates to 60 m/s to the east in 10 s. What is the buses acceleration? 2. A car traveling at 10.0 m/s to the west acce

professor190 [17]

Answers:

1) $a=6\frac{m}{s^{2}}$

2) $t=8s$

Explanation:

1) Acceleration $a$ is defined as the variation of Velocity $V$ in time $t$ :

$a=\frac{V}{t}$ (1)

A body also has acceleration when it changes its direction.

In this case we have a bus with a velocity of 60m/s to the east, that accelerates in a time 10s. So, we have to find the bus's acceleration:

$a=\frac{60m/s}{10s}$ (2)

$a=6m/s^{2}$ (3) This is the bus's accelerration

2) Now we have a car that accelerates $2m/s^{2}$ to the west in order to reach a speed of $16m/s$ in the same direction, and we have to find the time $t$ it takes to the car to reach that velocity.

Therefore we have to find $t$ from (1):

$t=\frac{V}{a}$ (4)

$t=\frac{16m/s}{2m/s^{2}}$ (5)

Finally:

$t=8s$ (6)

3 0

3 years ago