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3 years ago

When an object has its motion changed, the cause is generally __________.

2 answers:

8 0

When an object has its motion changed, the cause is generally an external force. The answer is letter A. It follows Newton’s second law of motion wherein a body is at rest and remains at rest without an external force applied to move the body.

zhuklara [117]3 years ago

8 0

A. an external force

just took the test on edge

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solar energy warms most of the earths surface

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2 years ago

9. If the musician hit the drum on a stage, how would the sound wave behave differently if he hit it the drum if the drum were s

egoroff_w [7]

I think it would be yes because the drum is submerged in water and the water would slow the sound waves, making the sound softer. Right?

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3 years ago

starting from a stop a traffic signal, a car speeds up to 20 m/s in 5 seconds. calculate the acceleration of the car.

Ira Lisetskai [31]

Answer:

5.867 m/s^2

Explanation:

Initial Speed > 0 m/s

Final Speed > 20 m/s

Time > 5 sec.

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3 years ago

a force of 25 newtons moves a box a distance of 4 meeters in 5 seconds.the work done on the box is ? NM and the power is. ? nm/

miskamm [114]

Answer:

The work done on the box is 100 Nm

The power is 20 Nm/s

Explanation:

There is a force 25 newtons moves a box a distance of 4 meters in

5 seconds

The work done on the box is the product of the force and the distance

that the box moves ⇒ work = force × distance

The force = 25 newtons

the distance = 4 meters

Work = 25 × 4 = 100 NM

The work done on the box is 100 Nm

The force moves the box 4 meters in 5 seconds

The power is the rate of work

The power = work ÷ time

The work = 100 Nm

The time = 5 seconds

The power = 100 ÷ 5 = 20 Nm/s

The power is 20 Nm/s

6 0

3 years ago

Two masses —m1 and m2— are connected by light cables to the perimeters of two cylinders of radii r1 and r2 respectively, as show

Aleksandr [31]

Answer:

Part a)

Mass of m2 is given as

$m_2 = \frac{20}{3} kg$

Part b)

Angular acceleration is given as

$\alpha = 1.96 rad/s^2$

Part c)

Tension in the rope is given as

$T = 176.6 N$

Explanation:

Part a)

When m1 and m2 both connected to the cylinder then the system is at rest

so we can use torque balance here

$m_1g r_1 = m_2 g r_2$

$20 g(0.5) = m_2 g(1.5)$

$10 = 1.5 m_2$

$m_2 = \frac{20}{3} kg$

Part b)

When block m_2 is removed then system becomes unstable

so force equation of mass m1

$m_1g - T = m_1 a$

also we have

$T r_1 = I\alpha$

now we have

$m_1g = \frac{I a}{r_1^2} + m_1 a$

$a = \frac{m_1g}{\frac{I}{r_1^2} + m_1}$

$a = \frac{20 (9.81)}{\frac{45}{0.5^2} + 20}$

$a = 0.981 m/s^2$

so angular acceleration is given as

$\alpha = \frac{a}{r_1}$

$\alpha = \frac{0.981}{0.5}$

$\alpha = 1.96 rad/s^2$

Part c)

Tension in the rope is given as

$T = \frac{I\alpha}{r_1}$

$T = \frac{45 (1.96)}{0.5}$

$T = 176.6 N$

7 0

3 years ago