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
frozen [14]
3 years ago
7

A rock is thrown straight up. What is the net external force acting on the rock when it is at the top of its trajectory (ignorin

g ar resistance)? a)There is none b)Gravity c)A normal force d)Thrust
Physics
1 answer:
Nat2105 [25]3 years ago
8 0

Answer:

b) Gravity

Explanation:

Gravity acts all of the time, when you apply force to a projectile it has to be more than the forces of the gravity and air resistance together so the projectile can move,  when the rock is at the top of its trajectory the force that you applied at the beginning is getting lost, so the other forces (air resistance and gravity) make the rock fall to the floor.

You might be interested in
Pls help
belka [17]

Answer:

2156 J

Explanation:

From the question,

Work done = Combined mass of the bucket and water×height×gravity.

W = (M+m)hg............................. Equation 1

Where M = mass of water, m = mass of the bucket, h = height, g = acceleration due to gravity.

Given: M = 20 kg, m = 2 kg, h = 10 m

Constant: g = 9.8 m/s²

Substitute these  value into equation 1

W = (20+2)×10×9.8

W = 22×98

W = 2156 J

4 0
2 years ago
A commonly used unit of electrical energy.
ladessa [460]
The two most common units of electric energy is Watts or hertz.
8 0
3 years ago
Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill?
Tema [17]
<span>Kinetic energy increases and potential energy decreases.
</span>
6 0
3 years ago
Read 2 more answers
A 2-kg box is pushed by a force of 4 N for 2 seconds. It has an initial velocity vo = 2 m/s to the right. NOTE: Since this probl
IRISSAK [1]

Answer:

Kf= 36 J

W(net) = 32 J

Explanation:

Given that

m = 2 kg

F= 4 N

t= 2 s

Initial velocity ,u= 2 m/s

We know that rate of change of linear momentum is called force.

F= dP/dt

F.t = ΔP

ΔP = Pf - Pi

ΔP = m v  - m u

v= Final velocity

By putting the values

4 x 2 = 2 ( v - 2)

8 =  2 ( v - 2)

4 = v - 2

v= 6 m/s

The final kinetic energy Kf

Kf= 1/2 m v²

Kf= 0.5 x 2 x 6²

Kf= 36 J

Initial kinetic energy Ki

Ki = 1/2 m u²

Ki= 0.5 x 2 x 2²

Ki = 4 J

We know that net work is equal to the change in kinetic energy

W(net) = Kf - Ki

W(net) = 36 - 4

W(net) = 32 J

7 0
3 years ago
A runner traveled 15 kilometers north then backtracked 11 kilometers south before stopping. His resultant displacement was
Serhud [2]

<u>Answer:</u>

 Resultant displacement is 4 km north.

<u>Explanation:</u>

    Let east represents positive x- axis and north represent positive y - axis. Horizontal component is i and vertical component is j.

   A runner traveled 15 kilometers north then backtracked 11 kilometers south before stopping,

   So initial displacement, 15 kilometers north = 15 j km

        Second displacement, 11 kilometers south = -11 j km

   Total displacement = 15 j -11 j = 4 j km

   Total displacement is 4 km north.

4 0
3 years ago
Read 2 more answers
Other questions:
  • If you want to play a tune on wine glasses, you’ll need to adjust the oscillation frequencies by adding water to the glasses. Th
    12·1 answer
  • One of the longer sides of a kite is 39 feet. one of the shorter sides is 25 feet. half the length of the shorter diagonal is 15
    13·1 answer
  • Normally, atoms are electrically neutral because there are__.
    10·1 answer
  • Which of these observations would most likely be seen in stage N
    9·1 answer
  • The combination of all forces that act on an object are (2 points)
    14·1 answer
  • The use of a beat or a rhythm to remember something is
    8·2 answers
  • A student is building a simple circuit with a battery, light bulb, and copper wires. When she connects the wires to the battery
    11·2 answers
  • In today's world, scientists can tell that
    5·2 answers
  • GIVING BRAINLIEST FIVE STARS AND HEART!
    8·1 answer
  • What’s up world or people
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!