water leaves a hose at a rate of 1.5 kg/s with a speed of 20m/s and its aimed at the side of a car, then splashes back from the car at a speed of 18m/s. what is the average force between the water and car during contact?

Need to know how long the water is in contact with the car.

Ft = Δmv

To determine the average force between the water and the car during contact, we can use Newton's second law of motion, which states that force (F) is equal to the rate of change of momentum (Δp) over time (Δt).

First, let's calculate the momentum of the water before and after it hits the car:

1. The momentum of the water before it hits the car can be calculated using the formula:
momentum = mass × velocity

Given:
mass of water leaving the hose per second (m) = 1.5 kg/s
velocity of the water leaving the hose (v1) = 20 m/s

Momentum before = m × v1

2. The momentum of the water after it hits the car can also be calculated using the formula:
momentum = mass × velocity

Given:
velocity of the water after hitting the car (v2) = -18 m/s
(-18 m/s indicates the opposite direction of the water's initial velocity, as it splashes back)

Momentum after = m × v2

Now, to determine the average force between the water and the car, we need to calculate the change in momentum (Δp) and time (Δt):

Δp = Momentum after - Momentum before
Δt = Time interval of contact

Finally, we can calculate the average force (F) by dividing the change in momentum by the time interval:

F = Δp / Δt

Remember, force is a vector quantity, so it will have both magnitude and direction. The direction of the average force would be opposite to the direction of the water's initial velocity.

Let's calculate it step by step:

Step 1: Calculate the momentum before the water hits the car.
Momentum before = mass × velocity
Momentum before = 1.5 kg/s × 20 m/s

Step 2: Calculate the momentum after the water hits the car.
Momentum after = mass × velocity
Momentum after = 1.5 kg/s × -18 m/s

Step 3: Calculate the change in momentum.
Δp = Momentum after - Momentum before

Step 4: Determine the time interval of contact.
This information is not given in the question, so we do not currently have enough information to calculate the average force accurately.