If she returned home by the same path 7 h 30 min after she left, what were her average speed and velocity in km/h for the entire trip

speed  v = 0.148 m / s

velocity   v = 0

Explanation:

In this exercise we must be careful that the speed is a scalar and the speed is a vector, let's start by looking for the speed

           v = Δx /Δt

the distance traveled is x = 2d and the time taken is

           t = 7h 30 min

let's reduce to seconds

          t = 7 h 3600s / 1h + 30 min 60s / 1min = 27000 s

so the speed is

          v = 2d / 27000

to finish the calculation suppose a distance traveled d = 2000 m

          v = 2 2000/27000

          v = 0.148 m / s

this is the raides which is the speed module

Velocity is a vector,

          v = Dx / Dt

in this case the displacement is

           Dx = d -d

           Dx = 0

the total displacement is zero since it returns to the starting point, consequently the velocity is zero

          v = 0

bold is a vector

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance         (d) = 3 feet

time taken to lift                         (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

                  1 h.p   = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

                      h.p = (force × distance)/ time

                            = (10 × 3)/ 10

                            = 30/10

                            = 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts

1 a

2 b

3 b

4 d

5 d

6 d

explanation: