Question

Груз массой 10 кг падает с некоторой высоты и достигает поверхности Земли через 2,5 с. Найти Работу

Answer 1

Дано t=2,5 с m=10 кг   А- ?

А=m*g*h

h=g*t^2/2=10*6,25/2=31,25 м
А=10*10*31,25=3125 Дж

Answer 2

Calculation of Work Done

To calculate the work done when a mass of 10 kg falls from a certain height and reaches the surface of the Earth in 2.5 seconds, we need to use the formula for work:

Work (W) = Force (F) × Distance (d) × cos(θ)

In this case, the force acting on the mass is its weight, which can be calculated using the formula:

Weight (F) = mass (m) × gravitational acceleration (g)

The distance traveled by the mass is the height from which it falls. However, the angle (θ) between the force and the direction of motion is not given, so we will assume that the force and the direction of motion are in the same line, making the angle 0 degrees.

Let's calculate the work done step by step:

1. Calculate the weight of the mass: - The mass is given as 10 kg. - The gravitational acceleration on Earth is approximately 9.8 m/s^2.

Weight (F) = 10 kg × 9.8 m/s^2 = 98 N.

2. Calculate the distance traveled by the mass: - The time taken to reach the surface of the Earth is given as 2.5 seconds. - The formula to calculate the distance traveled by a falling object is:

d = (1/2) × g × t^2

where g is the gravitational acceleration and t is the time.

Substituting the values:

d = (1/2) × 9.8 m/s^2 × (2.5 s)^2 = 30.625 m.

3. Calculate the work done: - Since the angle (θ) is assumed to be 0 degrees, the cosine of 0 degrees is 1.

Work (W) = 98 N × 30.625 m × cos(0°) = 2987.75 J.

Therefore, the work done when a mass of 10 kg falls from a certain height and reaches the surface of the Earth in 2.5 seconds is 2987.75 Joules.