Question

On a highway, a car is driven 80. kilometers

Answer 1

The average speed of the car for the entire trip can be calculate by using:

$v=\frac{S}{t}$

where S is the total distance covered by the car, and t is the total time taken.

The total distance travelled by the car is:

$S=80 km+50 km+40 km=170 km$

while the total time taken is:

$t=1.00 h+0.50 h+0.50 h=2.00 h$

so, the average speed of the car is:

$v=\frac{S}{t}=\frac{170 km}{2.00 h}=85 km/h$

so, the correct answer is (3) 85 km/h.

Answer 2

The average speed of the car for entire trip is $\boxed{85\text{ km/h}}$.

Further Explanation:

Speed is the measure of a quantity of an object the tells how fast the object is moving in the other words we can define the speed that it is the distance covered by an body divided by the time taken to cover that distance. It is a quantity with only magnitude so it is a scalar quantity.

The average speed is defined as the sum of all the distance traveled by the body divided by the sum of time taken to travel that distance.

Given:

The distance travel by the car is $80\text{ km}$ for $1.00\text{ hours}$.

The distance travel by the car is $50\text{ km}$ for $0.50\text{ hours}$.

The distance travel by the car is $40\text{ km}$ for .

$0.50\text{ hours}$.

Concept:

The expression for the average can be written as:

S =$\dfrac{{{\text{sum of distances }}}}{{{\text{sum of time}}}}$    …… (1)

The distance travel by the car is $80\text{ km}$ for $1.00\text{ hours}$, distance travel by the car is $50\text{ km}$ for $0.50\text{ hours}$ and distance travel by the car is $40\text{ km}$ for $0.50\text{ hours}$.

The sum of the distance is:

$\begin{aligned}D&=80{\text{ km}}+{\text{50 km}}+40{\text{ km}}\\&=170{\text{ km}}\end{aligned}$

The sum of time taken to travel the distance is:

$\begin{aligned}t&=1.00{\text{ h}} + 0.50{\text{ h}} + 0.50{\text{ h}}\\&=2.00{\text{ h}}\end{aligned}$

Substitute $170\text{ km}$ for total distance and $2.00\text{ h}$ for total time in equation (1).

$\begin{aligned}S&=\frac{{{\text{170 km}}}}{{2.00{\text{ h}}}}\\&=85{\text{ km/h}}\end{aligned}$

Therefore, the average speed of the car for entire trip is $\boxed{85\text{ km/h}}$.

Learn more:

1. Find the net force. https://brainly.in/question/8668644

2. Find the velocity. https://brainly.in/question/4502003

3. Calculate average speed brainly.com/question/11597590

Answer Details:

Grade: Middle school

Subject: Physics

Chapter: Kinematics

Keywords:

Highway, car, driven, 80 km, 1.00 hour, 1.00 hr, 1.00 h, 50 km, 0.50 hour, 0.50 hr, 0.50 h, 50  km, average speed, entire, trip, 85 km/hr.