Como se dice casa en náhuatl

A student walks 144 m west, and then turns around and walks 89 m east If this takes place in a 7.5-minute interval, what is the

Darina [25.2K]

The average speed is 0.517 m/s

The average velocity is 0.12 m/s west

Explanation:

When dividing the total distance covered by object by time, we get the value for average speed.

$\text { speed }=\frac{\text {distance}}{\text {time}}$

Calculate the distance without consideration of motion’s direction. So, the distance walks 144 m first, and then another 89 m, so the total distance covered is

d = 144 + 89 = 233 meters

Given t = 7.5 minutes. Convert minute into seconds,

$7.5 \times 60=450 \text { seconds }$

So, the average speed can be calculates as below,

$\text { speed }=\frac{233}{450}=0.517 \mathrm{m} / \mathrm{s}$

When dividing the object’s displacement by time taken, we can calculate average velocity.

$\text {velocity}=\frac{\text {displacement}}{\text {time}}$

In given case, the students walks 144 m west first, and then 89 m east. The displacement is the distance in a straight line between the initial and final position: therefore, in this case, the displacement is

d = 144 (west) - 89 (east) = 55 m (west)

The time taken is t = 450 s

So, the average velocity is

$\text {velocity}=\frac{55}{450}=0.12 \mathrm{m} / \mathrm{s}$

And the direction is west (the same as the displacement).

8 0

4 years ago

A 2578-kg van runs into the back of a 825-kg compact car at rest. They move off together at 8.5 m/s. Assuming the friction with

allochka39001 [22]

Answer:

The initial speed of the car = 11.22 m/s

Explanation:

Law of conservation of energy: It states that when two bodied collide in a closed system, the sum of momentum before collision is equal to the sum of momentum after collision.

Note: A close system is one that is free from from external forces. E.g Frictional force.

From the law of conservation of momentum,

Total momentum before collision = Total momentum after collision.

m₁u₁ + m₂u₂ = (m₁ + m₂)V..................... Equation 1

Where m₁ = mass of the van, m₂ = mass of the car, u₁ = initial velocity of the van, u₂ = initial velocity of the car, V = Common velocity.

Given: m₁ = 2578 kg, m₂ = 825 kg, u₂ = 0 ( the car was at rest), V= 8.5 m/s

Substituting these values into equation 1, and solving for u₁

2578(u₁) + (825 × 0) = (2578 + 825)8.5

2578u₁ = 28925.5

Dividing both side of the equation by the coefficient of u₁

2578u₁/2578 = 28925.5/2578

u₁ = 11.22 m/s