Question

A car traveling with constant speed travels 150 km in 7200 s. What is the speed of the car?

Answer 1

Answer:

The speed of the car to 2 significant figures is $\boxed{21\,{{\text{m}} \mathord{\left/{\vphantom {{\text{m}} {\text{s}}}} \right.\kern-\nulldelimiterspace} {\text{s}}}}$ .

Further Explanation:

Given:

The distance covered by the car is $150\,{\text{km}}$.

The time taken by the car to cover the distance is $7200\,{\text{s}}$ .

Concept:

The speed of a car defined as the ratio of the distance and the time taken by the car in covering that distance.

Write the expression for the speed of the car as:

 $v = \dfrac{{{\text{distance}}}}{{{\text{time}}}}$    …… (1)                                        

Here, $v$ is the speed of the car.

The distance covered by the car in meters is.

 $\begin{aligned}d&= 150 \times {\text{1000}}\,{\text{m}}\\{\text{ 1}}&={\text{.50}} \times {\text{1}}{{\text{0}}^5}\,{\text{m}}\\\end{aligned}$

Substitute the values in the above expression.

 $\begin{aligned}v&= \frac{{1.50 \times {{10}^5}\,{\text{m}}}}{{7200\,{\text{s}}}}\\&= \frac{{1500}}{{72}}\,{{\text{m}} \mathord{\left/ {\vphantom {{\text{m}} {\text{s}}}} \right.\kern-\nulldelimiterspace} {\text{s}}}\\&= 20.83\,{{\text{m}} \mathord{\left/{\vphantom {{\text{m}} {\text{s}}}} \right.\kern-\nulldelimiterspace} {\text{s}}}\\&\approx 21\,{{\text{m}} \mathord{\left/{\vphantom {{\text{m}} {\text{s}}}} \right.\kern-\nulldelimiterspace} {\text{s}}}\\\end{aligned}$

Thus, the speed of the car to 2 significant figures is $\boxed{21\,{{\text{m}} \mathord{\left/{\vphantom {{\text{m}} {\text{s}}}} \right.\kern-\nulldelimiterspace} {\text{s}}}}$ .

Learn More:

1. A test car travels in a straight line along the x axis, the graph in the figure shows brainly.com/question/10772739
2. If no friction acts on a diver during a dive, then which of the following statements is true brainly.com/question/4633609
3. A 1500-kg car accelerates from rest to 25 m/s in 7.0 s. What is the average power delivered by the brainly.com/question/7956557

Answer Details:

Grade: Middle School

Chapter: Speed and distance

Subject: Physics

Keywords: Speed, velocity, distance, time, distance of 150 km, in 7200 s, speed of the car, ratio of distance, rate of change of distance, 20.83 m/s, 21m/s.

Answer 2

The speed of the car is 75 km/h

Further explanation

These are the formulas that we have to remember before solving the problem.

Speed is the rate of change of distance.

$\large { \boxed {v = \frac{d}{t}}}$

v = speed ( m/s )

d = distance ( m )

t = time ( s )

Acceleration is the rate of change of velocity.

$\large { \boxed {a = \frac{\Delta v}{t}}}$

a = acceleration ( m/s² )

Δv = change in speed ( m/s )

t = time ( s )

Let us now tackle the problem!

Given:

distance = d = 150 km

time taken = t = 7200 s = 2 hours

Unknown:

velocity = v = ?

Solution:

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

$v = \frac{150}{2}$

$\large {\boxed {v = 75~km/h} }$

The acceleration of the car is 0 m/s² because it travels with constant speed.

We could also plot the distance vs time graph as shown in the attachment.

Learn more

• Velocity of A Runner : brainly.com/question/3813437
• Kinetic Energy : brainly.com/question/692781
• Acceleration : brainly.com/question/2283922

Answer details

Grade: Middle School

Subject: Physics

Chapter: Kinematics

Keywords: indycar top speed of a fastest police car has ever gone