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
Ksenya-84 [330]
3 years ago
15

When throwing a ball upwards, the velocity is positive, and the acceleration is negative. True of False?

Physics
1 answer:
Setler79 [48]3 years ago
3 0

Answer:

The velocity & acceleration will be taken as negative when a ball is thrown upward because work is done against the gravity.

Explanation:

You might be interested in
Acceleration = change of velocity divided by time interval = Δv/Δt.
MariettaO [177]

Answer:

a=2.378 m/s^2

Explanation:

a=Δv/Δt------eq(1)

Δv=Vf-Vi=120 km/h-0 km/h=120 km/h

or Δv=33.3 m/sec

or time=t=14s

putting values in eq(1)

a=33.3/14

a=2.378 m/s^2

6 0
3 years ago
LOTS OF POINTSA rocket of mass 40 000 kg takes off and flies to a height of 2.5 km as its engines produce 500 000 N of thrust.
Svetradugi [14.3K]

Answer:

i) E = 269 [MJ]    ii)v = 116 [m/s]

Explanation:

This is a problem that encompasses the work and principle of energy conservation.

In this way, we establish the equation for the principle of conservation and energy.

i)

E_{k1}+W_{1-2}=E_{k2}\\where:\\E_{k1}= kinetic energy at moment 1\\W_{1-2}= work between moments 1 and 2.\\E_{k2}= kinetic energy at moment 2.

W_{1-2}= (F*d) - (m*g*h)\\W_{1-2}=(500000*2.5*10^3)-(40000*9.81*2.5*10^3)\\W_{1-2}= 269*10^6[J] or 269 [MJ]

At that point the speed 1 is equal to zero, since the maximum height achieved was 2.5 [km]. So this calculated work corresponds to the energy of the rocket.

Er = 269*10^6[J]

ii ) With the energy calculated at the previous point, we can calculate the speed developed.

E_{k2}=0.5*m*v^2\\269*10^6=0.5*40000*v^2\\v=\sqrt{\frac{269*10^6}{0.5*40000} }\\ v=116[m/s]

8 0
3 years ago
You drop a pencil from your desk, which is 1 meter above the floor. How long does it take for the pencil to hit the floor? How f
vova2212 [387]

Answer:

1. 0.45 s.

2. 4.41 m/s

Explanation:

From the question given above, the following data were obtained:

Height (h) = 1 m

Time (t) =?

Velocity (v) =?

1. Determination of the time taken for the pencil to hit the floor.

Height (h) = 1 m

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =?

h = ½gt²

1 = ½ × 9.8 × t²

1 = 4.9 × t²

Divide both side by 4.8

t² = 1/4.9

Take the square root of both side

t = √(1/4.9)

t = 0.45 s.

Thus, it will take 0.45 s for the pencil to hit the floor.

2. Determination of the velocity with which the pencil hit the floor.

Initial velocity (u) = 0 m/s

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) = 0.45 s.

Final velocity (v) =?

v = u + gt

v = 0 + (9.8 × 0.45)

v = 0 + 4.41

v = 4.41 m/s

Thus, the pencil hit the floor with a velocity of 4.41 m/s

6 0
3 years ago
In 1990, the Human Genome Project began with the stated goal to ______.
galina1969 [7]
As far as I remember, in 1990, the Human Genome Project began with the stated goal to l<span>ocate the specific genes that cause given diseases.</span>
7 0
4 years ago
Read 2 more answers
Hey, guys need your help. I do school online and I have this project due. The problem is, I didn't know I needed most of these s
Alexxandr [17]
You need to post a picture so someone can help
6 0
3 years ago
Other questions:
  • Approximately how far is the sun from the center of the milky way galaxy?
    12·2 answers
  • Which question would most likely fill in the blank
    6·1 answer
  • 2. Jessie studies seaweed and she usually takes large amounts of samples. She would take
    7·1 answer
  • If a rigid body rotates about point O, the sum of the moments of the external forces acting on the body about point O equals whi
    11·1 answer
  • The gravitational force of attraction between two students sitting at their desks in physics class is 2.59 × 10−8 N. If one stud
    6·2 answers
  • What has happened to the amount of water in the high plains aquifer over time
    13·1 answer
  • Explain the energy changes involved when a positive charge moves because of a nearby, negatively charged object. use the terms e
    14·2 answers
  • If two capacitors, A and B, have the same area and dielectric constant, but the distance between the plates of A is twice the di
    13·1 answer
  • Aluminium is metal or metalloid
    13·2 answers
  • Please only answer if you are positive. Thanks! Brainliest if correct!
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!