answer.
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
Anuta_ua [19.1K]
2 years ago
9

A rope exerts a force F on a 20.0-kg crate. The crate starts from rest and accelerates upward at 5.00 m/s2 near the surface of t

he earth. What is the kinetic energy (in J) of the crate when it is 4.0 m above the floor?
Physics
1 answer:
tia_tia [17]2 years ago
5 0

Answer:

400 J

Explanation:

Given:

Δy = 4.00 m

v₀ = 0 m/s

a = 5.00 m/s²

Find: v²

v² = v₀² + 2aΔy

v² = (0 m/s)² + 2 (5.00 m/s²) (4.00 m)

v² = 40.0 m²/s²

Find KE:

KE = ½ mv²

KE = ½ (20.0 kg) (40.0 m²/s²)

KE = 400 J

You might be interested in
Whenever important physicists are discussed, Galileo Galilei, Isaac Newton, and Albert Einstein seem get the most attention. How
nordsb [41]
Larry Finkelstein, Norman Fischer, and Cassius Schwartz have been overlooked, in my opinion.
8 0
1 year ago
A traditional set of cycling rollers has two identical, parallel cylinders in the rear of the device that the rear tire of the b
mars1129 [50]

Answer:

ω2  =  216.47 rad/s

Explanation:

given data

radius r1 =  460 mm

radius r2 = 46 mm

ω =  32k rad/s

solution

we know here that power generated by roller that  is

power = T. ω    ..............1

power = F × r × ω

and this force of roller on cylinder is equal and opposite force apply by roller

so power transfer equal in every cylinder so

( F × r1 × ω1)  ÷ 2 = (  F × r2 × ω2 )  ÷  2    ................2

so

ω2  =  \frac{460\times 32}{34\times 2}

ω2  =  216.47

8 0
2 years ago
A heavy stone of mass m is hung from the ceiling by a thin 8.25-g wire that is 65.0 cm long. When you gently pluck the upper end
Triss [41]

Answer: m= 35.6 kg

Explanation:

For finding the mass of the stone we have the formula

v= \sqrt{\frac{Tension}{Linear. Mass. density} }

Here, Tension= m*g = m*9.81

and linear mass density= \frac{8.25 g}{65 cm}

Linear mass density= \frac{8.25*10^-3}{65*10^-2}

Linear mass density= 0.0127 kg/m

Velocity= 2*\frac{l}{t}

Velocity= 2 * \frac{65*10^-2}{7.84}

Velocity= 165.8 m/s

So putting all these values in equation we get

v= \sqrt{\frac{Tension}{Linear. Mass. density} }

165.8= \sqrt{\frac{m*9.81}{0.0127} }

Solving we get

m= 35.58 kg

or m= 35.6 kg

3 0
2 years ago
A professor's office door is 0.99 m wide, 2.2 m high, 4.2 cm thick; has a mass of 27 kg, and pivots on frictionless hinges. A "d
ANEK [815]

Answer:

I=8.8209\ kg.m^2

\alpha=0.6348\ rad.s^{-2}

Explanation:

Given:

  • width of door, w=0.99\ m
  • height of the door, h=2.2\ m
  • thickness of the door, t=4.2\ cm
  • mass of the door, m=27\ kg
  • torque on the door, \tau=5.6\ N.m

<em>∵Since the thickness of the door is very less as compared to its other dimensions, therefore we treat it as a rectangular sheet.</em>

  • For a rectangular sheet we have the mass moment of inertia inertia as:

I=\frac{1}{3} m.w^2

I=\frac{1}{3}\times 27\times 0.99^2

I=8.8209\ kg.m^2

We have a relation between mass moment of inertia, torque and angular acceleration as:

\alpha=\frac{\tau}{I}

\alpha=\frac{5.6}{8.8209}

\alpha=0.6348\ rad.s^{-2}

6 0
2 years ago
A projectile is launched horizontally east at a speed of 29.4 M/s towards a wall 88.2 m away. What is the velocity of the projec
Drupady [299]

Time before projectile hits wall

= 88.2 m / 29.4 m/s = 3 seconds

Vertical velocity of projectile after three seconds

= 3*9.8 = 29.4 m/s

Horizontal velocity of projectile after three seconds, assuming no air resistance

= 29.4 m/s  (given)

Conclusion:

velocity of projectile when it hits the wall

= < 29.4, -29.4> m/s

= sqrt(29.4^2+29.4^2) m/s east-bound at 45 degrees below horizontal

= 41.58 m/s east-bound at 45 degrees below horizontal.

6 0
2 years ago
Other questions:
  • A cheetah can run at 30 m/s, but only for about 12s. How far will it run in that time
    12·1 answer
  • An airplane is flying at a constant speed in a positive direction. It slows down when it approaches the airport where it's going
    13·1 answer
  • What is the unresolved problem that is facing scientists on the island of Guam?
    7·1 answer
  • While a roofer is working on a roof that slants at 38.0 ∘ above the horizontal, he accidentally nudges his 95.0 n toolbox, causi
    13·1 answer
  • if it takes 3.5 hours for the hogwarts express moving at a speed of 120 mi/hr to make it from platform 9 and 3/4 to hogwarts how
    5·1 answer
  • Anjali's plane had been flying through calm skies (no wind) with a velocity (speed and direction) vector <img src="https://tex.z
    11·1 answer
  • You place a 3.0-m-long board symmetrically across a 0.5-m-wide chair to seat three physics students at a party at your house. If
    9·1 answer
  • Three crates with various contents are pulled by a force Fpull=3615 N across a horizontal, frictionless roller‑conveyor system.
    12·1 answer
  • A farmer lifts his hay bales into the top loft of his barn by walking his horse forward with a constant velocity of 8 ft/s. Dete
    5·1 answer
  • Which illustration represents the arrangement of particles in a gas?
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!