1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
yanalaym [24]
3 years ago
15

A car increases velocity from 30 m/s to 60 m/s in 4 seconds. Calculate the average acceleration of the car over this time.

Physics
1 answer:
Lilit [14]3 years ago
3 0

Answer:

B.7.5m/s2

Explanation:

average acceleration=change invelocity/time taken

a=(60-30)/4

=7.5m/s2

You might be interested in
video for A door 1 m wide, of mass 15 kg, is hinged at one side so that it can rotate without friction about a vertical axis. It
natka813 [3]

Answer:

\omega_f = 0.4\ rad/s

Explanation:

given,

width of door dimension  = 1 m

mass of door = 15 Kg

mass of bullet = 10 g = 0.001 Kg

speed of bullet = 400 m/s

I_{total} =I_{door} + I_{bullet}

I_{total} =\dfrac{1}{3}MW^2 + m(\dfrac{W}{2})^2

a) from conservation of angular momentum  

L_i = L_f  

mv\dfrac{W}{2} = I_{total}\omega_f  

mv\dfrac{W}{2}= (\dfrac{1}{3}MW^2 + m(\dfrac{W}{2})^2)\omega_f

\omega_f= \dfrac{mv\dfrac{W}{2}}{\dfrac{1}{3}MW^2 + m(\dfrac{W}{2})^2}

\omega_f= \dfrac{\dfrac{mv}{2}}{\dfrac{MW }{3}+(\dfrac{mW}{4})}

\omega_f= \dfrac{\dfrac{0.01\times 400}{2}}{\dfrac{15\times 1 }{3}+(\dfrac{0.01\times 1}{4})}

\omega_f = 0.4\ rad/s

8 0
3 years ago
Homeostasis is the regulation of an organism’s internal environment to maintain conditions suitable for life. Homeostasis requir
kherson [118]
I think it would be B
5 0
3 years ago
Read 2 more answers
What is one latitude where there is no continental barriers?
AveGali [126]
The equator has no continental borders.
5 0
3 years ago
Read 2 more answers
A 4 kg textbook sits on a desk. It is pushed horizontally with a 50 N applied force against a 15 N frictional force.
GarryVolchara [31]

a) See free-body diagram in attachment

b) The book is stationary in the vertical direction

c) The net horizontal force is 35 N in the forward direction

d) The net force on the book is 35 N in the forward horizontal direction

e) The acceleration is 8.75 m/s^2 in the forward direction

Explanation:

a)

The free-body diagram of a body represents all the forces acting on the body using arrows, where the length of each arrow is proportional to the magnitude of the force and points in the same direction.

From the diagram of this book, we see there are 4 forces acting on the book:

- The applied force, F = 50 N, pushing forward in the horizontal direction

- The frictional force, F_f = 15 N, pulling backward in the horizontal direction (the frictional force always acts in the direction opposite to the motion)

- The weight of the book, W=mg, where m is the mass of the book and g=9.8 m/s^2 is the acceleration of gravity, acting downward. We can calculate its magnitude using the mass of the book, m = 4 kg:

W=(4)(9.8)=39.2 N

- The normal reaction exerted by the desk on the book, N, acting upward, and balancing the weight of the book

b)

The book is in equilibrium in the vertical direction, therefore there is no motion.

In fact, the magnitude of the normal reaction (N) exerted by the desk on the book is exactly equal to the weight of the book (W), so the equation of motion along the vertical direction is

N-W=ma

where a is the acceleration; however, since N = W, this becomes

a=0

And since the book is initially at rest on the desk, this means that there is no motion.

c)

We said there are two forces acting in the horizontal direction:

- The applied force, F = 50 N, forward

- The frictional force, F_f = 15 N, backward

Since they act along the same line, we can calculate their resultant as

\sum F = F - F_f = 50 - 15 = 35 N

and therefore the net force is 35 N in the forward direction.

d)

The net force is obtained as the resultant  of the net forces in the horizontal and vertical direction. However, we have:

- The net force in the horizontal direction is 35 N

- The net force in the vertical direction is zero, because the weight is balanced by the normal reaction

Therefore, this means that the total net force acting on the book is just the net force acting on the horizontal direction, so 35 N forward.

e)

The acceleration of the book can be calculated by using Newton's second law:

\sum F = ma

where

\sum F is the net force

m is the mass

a is the acceleration

Here we have:

\sum F = 35 N (in the forward direction)

m = 4 kg

Therefore, the acceleration is

a=\frac{\sum F}{m}=\frac{35}{4}=8.75 m/s^2 (forward)

Learn more about forces, weight and Newton's second law:

brainly.com/question/8459017

brainly.com/question/11292757

brainly.com/question/12978926

brainly.com/question/11411375

brainly.com/question/1971321

brainly.com/question/2286502

brainly.com/question/2562700

#LearnwithBrainly

8 0
3 years ago
Janelle is exploring the relationship between the brightness of a light bulb and the current that powers it. When applying these
Vlada [557]

Answer:B

Explanation:

Y is the brightest bulb

7 0
3 years ago
Other questions:
  • What is pressure? A)Shown in picture B)Shown in picture C)Shown in picture D)Shown in picture
    14·1 answer
  • True or false? Nitrogen in the atmosphere is responsible for clouds and precipitation? If not what is?
    8·1 answer
  • You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you us
    12·2 answers
  • Which of the following statements best contrasts thermal energy transfer through radiation, conduction, and convection
    8·1 answer
  • Funtions of a fuse box​
    15·1 answer
  • (1) Calculate the buoyant force on a 2.00-L helium balloon.
    9·1 answer
  • Two ice skaters push off against one another starting from a stationary position. The 54.1-kg skater acquires a speed of 0.375 m
    7·1 answer
  • 5. Why are ceramics and plastics good insulators?
    9·1 answer
  • What is elastic potential energy and give and a example
    12·1 answer
  • A lightbulb has a power rating of 6.75 W and draws a current of 0.75 A when connected to a battery.
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!