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
Alenkinab [10]
3 years ago
12

A rock thrown straight up takes 4.2 s to reach its maximum height what was its initial velocity

Physics
1 answer:
liubo4ka [24]3 years ago
8 0

Consider the upward direction of motion as positive and downward direction of motion as negative.

a = acceleration due to gravity in downward direction = - 9.8 \frac{m }{s^{2}}

v₀ = initial velocity of rock in upward direction = ?

v = final velocity of rock at the highest point = 0 \frac{m }{s}

t = time to reach the maximum height = 4.2 sec

Using the kinematics equation

v = v₀ + a t

inserting the values

0 = v₀ + (- 9.8) (4.2)

v₀ = 41.2 \frac{m }{s}


You might be interested in
Help ASAP! Giving brainliest!!!
PilotLPTM [1.2K]
<h3><u>Answer and explanation;</u></h3>

Reflection;

  • Bounces back from an opaque material
  • Bounces back from the boundary of two mediums
  • Seen in mirrors

Refraction;

  • Passes through a prism  
  • Moves from one medium to another  
  • Seen in lenses

Reflection refers to the bouncing of waves such as light waves. It involves a change in direction of waves when they bounce off a barrier.

Refraction is the bending of waves when they move from one medium to another. It involves a change in the direction of waves as they pass from one medium to another.

8 0
3 years ago
Read 2 more answers
A gas undergoes a process in a piston–cylinder assembly during which the pressure-specific volume relation is pv1.3 = constant.
Galina-37 [17]

Answer:

Change in specific internal Energy=250\ \rm Btu/lb

Explanation:

Given:

  • Mass of the gas, m=0.4 lb
  • Initial pressure and volume are p_1=160\ \rm lbf/in^2\ and\ v_1=1\ \rm ft^3\\
  • Final pressure and temperature are p_1=480\ \rm lbf/in^2
  • Heat transfer from the gas is 2.1 Btu

Since the process is isotropic we have

p_1v_1^{1.3}=p_2v_2^{1.3}\\160\times 1^{1.3}=480\times v_2^{1.3}\\v_2=0.43\ \rm ft^3\\

So the final volume of the gas is calculated.

Work in any isotropic is given by w

w=\dfrac{p_1v_1-P_2v_2}{n-1}\\\\w=\dfrac{160\times1-480\times0.43}{1.3-1}\\w=-154.67\ \rm Btu\\

According to the first law of thermodynamics we have

Q=\Delta U+w\\-2.1=\Delta U-154.67\\\Delta U=152.56\ \rm Btu\\

So the Specific Internal Change is given by

\Delta u=\dfrac{\Delta U}{m}\\\Delta u=\dfrac{152.56}{0.4}\\\Delta u=250\ \rm Btu/lb

So the specific Change in Internal energy is calculated.

6 0
3 years ago
(a) The volume flow rate in an artery supplying the brain is 3.4 x 10-6 m3/s. If the radius of the artery is 5.6 mm, determine t
UNO [17]

Answer: a) speed = 3.45 × 10^-2 m/s

b) speed = 1.38 × 10^-1 m/s

Explanation: shown in the attachment

3 0
3 years ago
When do we land on Mars ?
lorasvet [3.4K]

Answer:

I think like 2024 or 25

Explanation:

Elon musk will probably go

5 0
3 years ago
Read 2 more answers
Match the following:
joja [24]

Explanation:

1. study of conversion of heat to mechanics → thermodynamics

A branch of physical science which deals with heat and other forms of energy.

2. The Law of Conservation of Energy  → first Law of Thermodynamics

Energy cannot be created nor be destroyed. According to first law of thermodynamics total energy of the system is always constant.

3. Result of applied energy  → work

Work is the way of system to release its energy.

4. Principle that states that in any energy transformation some energy is dissipated as heat  → Second Law of Thermodynamics

5. energy of motion  → kinetic energy

Kinetic energy is defined as energy possessed by the body due to its motion.

6. work/displacement  → force

Work is product of force and displacement.

Work=Force \times displacement

Force=\frac{Work}{displacement}

7. power · time  → energy

Power is defined energy per unit time.

Power=\frac{Energy}{Time}

Energy=Power\times Time

8. Device that transforms heat energy into mechanical energy →  heat engine

heat engine is a device which converts the heat energy which is released due to combustion of fuel into a useful work that is mechanical energy.

9 . Energy due to position  → potential energy

Potential energy is defined as energy possessed by the body due to its position.

10. efficiency of a heat engine unit of heat  → calorie

11. Measure of molecular motion  → Temperature

Kinetic energy is directly proportional to temperature.

Greater the motion more will be the kinetic energy and with more will be the temperature.

12. Heat given off by a liquid with no change in temperature  → latent heat of fusion

Latent heat of fusion is defined as heat released by 1 mole of substance when it under goes phase change that is from solid to liquid.

13. Motion within solids  → vibrational motion

Vibrational motion is the motion in which particle oscillates from its mean position.

14. Phase of matter on the sun → plasma

Plasma is hot ionized gas with equal number of positive and negative ions. Due to high temperature of sun most the gas are in the plasma state.

8 0
3 years ago
Other questions:
  • A 0.21 kg baseball moving at +25 m/s is slowed to a stop by a catcher who exerts a constant force of −360 N. a) How long does it
    7·1 answer
  • A truck covers 40.0 m in 7.50 s while uniformly slowing down to a final velocity of 2.55 m/s. (a) Find the truck's original spee
    14·1 answer
  • an object with a mass of 2.0 kg is accelerated at 5.0 m/s/s what is the net force that causes this acceleration
    8·1 answer
  • Diffusion of water through a differentially permeable membrane is called
    6·2 answers
  • cell membranes contain channels that allow K + ions to leak out consider channel that has diameter of nm and length of nm if cha
    7·1 answer
  • A steel rod has a length of 0.2 cm at 30 degrees C, what will be its length at 60 degrees C?
    11·1 answer
  • Use the information below for the next five questions:
    11·1 answer
  • Why is a protective apron or lab coat important to use when working with acids?
    15·2 answers
  • A hollow steel ball weighing 4 pounds is suspended from a spring. This stretches the spring 1515 feet. The ball is started in mo
    7·1 answer
  • A 16.0 kg canoe moving to the left at 12.5 m/s makes an elastic head on collision with a 14.0 kg raft moving to the right at 16.
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!