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3 years ago

A train travels 94 kilometers in 3 hours, and then 65 kilometers in 3 hours. What is its average speed?

Physics

2 answers:

Norma-Jean [14]3 years ago

8 0

The average speed of the train is about 26.5 kilometers per hour

const2013 [10]3 years ago

6 0

Average speed =

(total distance covered) / (total time to cover the distance) .

Total distance covered = (94km + 65 km) = 159 km.

Total time = (3 hr + 3 hr) = 6 hours

Average speed = (159 km) / (6 hours) = 26.5 km/hr .

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how long does it take adrian to reach his destination if his displacement is 253 meters and he walks north with a velocity of 1.

klemol [59]

Velocity = displacement/time

1.6 = 253/t

t = 158.125

It takes them about 158 seconds

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3 years ago

In a football game, a defensive lineman exerts a force upon an offensive lineman, causing the offensive lineman to be accelerate

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A car has a mass of 1000 kg and accelerates at 2 m/s2. What net force is exerted on the car?

prisoha [69]

Answer:

1000N

Explanation:

Based on force=mass*acceleration, if the acceleration is constant at 2 metres per second squared, 1,000kg*2m/s^2=2,000N of force.

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3 years ago

A uniform, 4.5 kg, square, solid wooden gate 2.0 mm on each side hangs vertically from a frictionless pivot at the center of its

True [87]

Answer:

The angular velocity is $w = 1.43\ rad/sec$

Explanation:

From the question we are told that

The mass of wooden gate is $m_g = 4.5 kg$

The length of side is L = 2 m

The mass of the raven is $m_r = 1.2 kg$

The initial speed of the raven is $u_r = 5.0m/s$

The final speed of the raven is $v_r = 1.5 m/s$

From the law of conservation of angular momentum we express this question mathematically as

Total initial angular momentum of both the Raven and the Gate = The Final angular momentum of both the Raven and the Gate

The initial angular momentum of the Raven is $m_r * u_r * \frac{L}{2}$

Note: the length is half because the Raven hit the gate at the mid point

The initial angular momentum of the Gate is zero

Note: This above is the generally formula for angular momentum of square objects

The final angular velocity of the Raven is $m_r * v_r * \frac{L}{2}$

The final angular velocity of the Gate is $\frac{1}{3} m_g L^2 w$

Substituting this formula

$m_r * u_r * \frac{L}{2} = \frac{1}{3} m_g L^2 w + m_r * v_r * \frac{L}{2}$

$\frac{1}{3} m_g L^2 w = m_r * v_r * \frac{L}{2} - m_r * u_r * \frac{L}{2}$

$\frac{1}{3} m_g L^2 w = m_r * \frac{L}{2} * [u_r - v_r]$

Where $w$ is the angular velocity

Substituting value

$\frac{1}{3} (4.5)(2)^2 w = 1.2 * \frac{2}{2} * [5 - 1.5]$

$6w = 4.2$

$w = \frac{6}{4.2}$

$w = 1.43\ rad/sec$

5 0

3 years ago

When adjusting the valve clearances on the engine, Technician A says the valves are closed when the valve lifter or follower is

andre [41]

Answer:

A. Technician A only

Explanation:

The camshaft opening ramp is what opens the valve, it starts at the basement of the inner circle and closes at the nose while the camshaft closing ramp allows for closing a valve starts at the nose and closes at the inner base circle. Valve clearance on an engine are performed when closing a valve, and is completed when the valve lifter or follower is on the inner base circle of the camshaft lobe.

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