EjerciciosFyQ

Acceleration and time taken by a car to increase speed (8329)

F_y_Q — 2024-10-10T03:34:15Z

A car, which has uniformly accelerated motion, increases its speed from 18 km/h to 72 km/h over a straight distance of 37.5 meters. Calculate the time taken for this journey and its acceleration.

To make the problem homogeneous, the first step is to express the speeds in SI units:

You can relate the change in speed and the distance covered with the car's acceleration:

Substitute the values and calculate:

The time needed to make this speed change is:

Substitute and calculate:

Calculation of braking acceleration (8312)

F_y_Q — 2024-09-16T03:46:33Z

Determine the acceleration of a car, initially moving at a speed of 120 km/h, knowing that it takes 20 seconds to come to a complete stop.

The car will have changed its speed by 120 km/h in those 20 seconds. First, convert the speed to International System units:

The acceleration will be:

Acceleration of an elevator with different readings on the weighing scale (7068)

F_y_Q — 2021-03-12T05:53:59Z

A person with a mass of 70 kg stands on a weighing scale in a moving elevator and observes different readings. Determine the acceleration of the elevator and wether it is moving up, down, accelereting, decelerating or stationary if the scale readings are: a) 66 kg, b) 74 kg and c) 70 kg.

Weight and normal force have opposite sense and the following equation is used:

Just substitute the values and calculate the acceleration in each case:

a)

The elevator is moving down.

b)

The elevator is moving up.

c)

The elevator is not moving.

Acceleration of a car (3583)

F_y_Q — 2016-05-22T06:35:14Z

A car is increasing its speed from 40 m/s to 70 m/s. What is its acceleration if the time needed was 3 seconds?

Acceleration is defined by:

Replace the problem data:

Descarga el enunciado y la resolución del problema en formato EDICO si lo necesitas.