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
zvonat [6]
4 years ago
6

. An object whose mass is 375 lb falls freely under the influence of gravity from an initial elevation of 253 ft above the surfa

ce of Earth. The initial velocity is downward with a magnitude of 10 ft/s. The effect of air resistance is negligible. (a) Determine the speed, in ft/s, of the object just before it strikes the surface of Earth. (b) Calculate the kinetic energy of the object, in Btu, before it strikes the surface of Earth. Assume that the gravitational acceleration is g
Physics
1 answer:
lozanna [386]4 years ago
3 0

Answer:

(a) Vf = 128 ft/s

(b) K.E = 122.8 Btu

Explanation:

(a)

In order to find the velocity of the object just before striking the surface of earth or the final velocity, we use 3rd equation of motion:

2gh = Vf² - Vi²

where,

g = 32.2 ft/s²

h = height = 253 ft

Vf = Final Velocity = ?

Vi = Initial Velocity = 10 ft/s

Therefore,

(2)(32.2 ft/s²)(253 ft) = Vf² - (10 ft/s)²

16293.2 ft²/s² + 100 ft²/s² = Vf²

Vf = √(16393.2 ft²/s²)

<u>Vf = 128 ft/s</u>

<u></u>

(b)

The kinetic energy of the object before it hits the surface of earth is given by:

K.E = (0.5)(m)(Vf)²

where,

m = mass of object = 375 lb

K.E = Kinetic energy of object before it strikes the surface of earth = ?

Therefore,

K.E = (0.5)(375 lb)(128 ft/s)²

K.E = 3073725 lb.ft²/s²

Now, converting this to Btu:

K.E = (3073725 lb.ft²/s²)(1 Btu/25037 lb.ft²/s²)

<u>K.E = 122.8 Btu</u>

You might be interested in
A plane mirror is placed to the right of an object. The image formed by the mirror will be a
guajiro [1.7K]

Answer:

A plane mirror is placed to the right of an object. The image formed by the mirror will be a virtual image that appears to be on the left of the mirror.

Explanation:

3 0
3 years ago
Read 2 more answers
every morning Tom walks along a straight road from his home to a bus stop,a distance of 160 meters.The graph shows his journey o
Assoli18 [71]

Answer:

Tom walked until he was 100 metres from his home. Then, he realised that he had dropped his homework, so he turned around and went 60 metres to pick it up again. He again turned back and started to walk faster to get to the bus stop on time. He got to the bus stop 100 seconds after leaving his home and waited for the bus.

Explanation:

4 0
3 years ago
List three examples of real science that you find on the internet or in real life
Darya [45]

for example

1. drinking water at least after 1 hour beacuse if we immediately drink water just after meal it dilutes the HCL produced in our stomach which hinders the digestion process

2.picking up tomatoes for salads which contains oxalic acid

3.Cutting apples which contains malic acid with knife then after sometimes it will trun into brown due to oxidation of iron present in a apple.

8 0
2 years ago
What is the purpose of scientific probes?
Genrish500 [490]
A scientific probe is a device that is sent to gather information from areas with harsh or dangerous conditions so as to not endanger humans. such devices may be sent to the sea floor, into a volcano, or into space. they collect information on those areas such as pressure, temperature, and makeup of the environment and send that information back to scientists so that they can evaluate and record that collected data.
8 0
4 years ago
Electrical current is defined as
lbvjy [14]

The answer is B. It is measured in amperes.

5 0
3 years ago
Other questions:
  • An object moves from the position +16m to the position +43m in 12s. What us the total displacement
    5·1 answer
  • Now assume that the pitcher in Part D throws a 0.145-kg baseball parallel to the ground with a speed of 32 m/s in the +x directi
    15·1 answer
  • Elements with low specific heat values have which characteristics
    7·1 answer
  • Identify and draw the forces that act on the pencil. Be certain to draw each force at the correct location (the point at which t
    8·1 answer
  • dayshawn is traveling at 12 m/s away from the school. dayshaun's mom is looking for him because he is late coming home so she le
    13·1 answer
  • A hoop and a disk with uniform mass distribution have the same radius but the total masses are not known. Can they both roll dow
    13·1 answer
  • A satellite orbits the Earth at constant speed. Is this an unbalanced or balanced force?
    8·1 answer
  • New York and Los Angeles are about 3000 mi apart, the time difference between these two cities is 3 h. Calculate the circumferen
    15·1 answer
  • A cork has weight mg and density 25% of water’s density. A string is tied around the cork and attached to the bottom of a water-
    15·1 answer
  • The speed of a wave is 50 cm/s and its wavelenght is 10 cm What is its frequency
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!