All categories

3 years ago

7. A car is travelling along a road at 30 ms when a pedestrian steps into the road 55 m ahead. The

Physics

1 answer:

trasher [3.6K]3 years ago

6 0

Answer: Car collide with man

Explanation:

Given

Speed of car is $u=30\ m/s$

Distance of the man from the car is $s=55\ m$

Reaction time $t_r=0.5\ s$

Rate of deceleration $a_d=-10\ m/s^2$

Distance traveled in the reaction time $d_o=30\times 0.5=15\ m$

Net effective distance to cover $d=55-15=40\ m$

Distance required to stop the car

$\Rightarrow v^2-30^2=2(-10)(s)\\\Rightarrow 0-900=-20s\\\Rightarrow s=45\ m$

Require distance is more than that of net effective distance. Hence, car collides with the man.

You might be interested in

Where does energy originate ina food web

ValentinkaMS [17]

$\huge{\underline{\underline{\red{Answer}}}}$

In a food web the energy is originated from the SUN.

4 0

3 years ago

Read 2 more answers

A spaceship is traveling toward Earth while giving off a constant radio signal with a wavelength of 1 meter (m). What will the s

Nadya [2.5K]

Answer:

Less than 1 m

Explanation:

When objects are getting closer to each other there is a slight change in the wavelength that is being transmitted by either objects. This is known as the blue shift of waves. Here, the wavelength reduces.

In the opposite case the when objects are getting farther from each other there is a slight change in the wavelength that is being transmitted by either objects. This is known as the red shift. Here, the wavelength increases.

In this case the spaceship is getting close to Earth hence the wavelength will be lower than 1 m.

4 0

3 years ago

Jake calculates that the frequency of a wave is 500 hertz and that the wave is moving at 1,250 m/s. What is the wavelength of th

Neko [114]

Frequency (f) = 500 hz (SI)
Velocity (V) = 1250 m/s (SI)
Wavelength (Lambda) = ? meters

$v = \lambda \times f$
$1250 = \lambda \times 500 \\ \lambda = 1250 \div 500 \\ \lambda = 2.5 \: meters$

6 0

3 years ago

A car with a total mass of 1800 kg (including passengers) is driving down a washboard road with bumps spaced 4.9 m apart. The ri

Drupady [299]

Answer:

k = 9.6 x 10^5 N/m or 9.6 kN/m

Explanation:

First, we need to use the expression to calculate the spring constant which is:

w² = k/m

Solving for k:

k = w²*m

To get the angular velocity:

w = 2πf

The problem is giving the linear velocity of the car which is 5.7 m/s. With this we can calculate the frequency of the car:

f = V/x

f = 5.7 / 4.9 = 1.16 Hz

Now the angular velocity:

w = 2π*1.16

w = 7.29 rad/s

Finally, solving for k:

k = (7.29)² * 1800

k = 95,659.38 N/m

In two significant figures it'll ve 9.6 kN/m

5 0

3 years ago

Read 2 more answers

Please help with these questions

lord [1]

When do you gotta turn it in?

8 0

2 years ago