Physics, 08.09.2020 04:01 Geo777

A ball is dropped from the top of a tower 40 m high. What is its velocity when it has covered 20 m? What would be its velocity when it hits the ground? Take g= 10 m/s²

Answers: 1

Show answers

Answers

Answer from: Wethepeeps6048

Given :

Height from which ball is dropped , h = 40 m .

Acceleration due to gravity , g= 10 m/s² .

Initial velocity , u = 0 m/s .

To Find :

Velocity when ball covered 20 m and velocity when it hit the ground .

Solution :

Now , height when ball covered 20 m distance is , 40 - 20 = 20 m .

By equation of motion :

$v^2=u^2+2gh\\\\v=\sqrt{2\times 10\times 20}\ m/s\\\\v=20\ m/s$

Now , distance covered when body reaches ground is , 40 m .

Putting value h = 40 m in above equation , we get :

$v=\sqrt{2\times 10\times 40}\ m/s\\\\v=20\sqrt{2}\ m/s$

Hence , this is the required solution .

Answer from: Quest

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

Answer from: Quest

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

$f\alpha \frac{dp}{dt}$

⇒ $f= k \frac{dp}{dt}$

here k is the proportionality constant whose value is 1.

$f=\frac{dp}{dt}$

$f= \frac{d[mv]}{dt}$

$f= m\frac{dv}{dt} +v\frac{dm}{dt}$

$f=ma+v\frac{dm}{dt}$ [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

Another question on Physics

Physics, 22.06.2019 07:50

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.

Answers: 2

Answer

Physics, 22.06.2019 10:00

If a stone with an original velocity of 0 is falling from a ledgeand takes 8 seconds to hoybthe ground whays the final velocity of the stone

Answers: 2

Answer

Physics, 22.06.2019 17:20

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b.b. at twice the distance, the magnitude of the field is 2b.c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.

Answers: 3

Answer

Physics, 22.06.2019 18:30

Which of the following is not a means to accelerating? question 4 options: a)increase speed b)remain still c)decrease speed d)change direction

Answers: 2

Answer

You know the right answer?

A ball is dropped from the top of a tower 40 m high. What is its velocity when it has covered 20 m?...

Questions