Question

Question)

a) What is the theory of Projectile Motion Experiment?

b) What is the scientific concept of this Projectile Motion Experiment? (Explain in 500 words)

c) What is the background information of the Projectile Motion Experiment?

Answer 1

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PROJECTILE MOTION

(a)Theory:-

  A Projectile or a projectile motion is an object thrown with some initial velocity and allowed them to travel under the force of gravity, following a particular trajectory, without being propelled by an engine. The object under projectile motion will experience a constant speed in horizontal direction and a constant acceleration of 9.8 m/s² in the vertical direction.

Horizontal motion of projectile

(b)

The speed in the horizontal direction is 'v_x' and this speed doesn't change. The equation which predicts the position at any time in the horizontal direction is simply,

             

Vertical motion of projectile

Because gravity has a downward pull, the vertical velocity changes constantly. The equation that predicts the vertical velocity at any time 'v_y' is

                                                              

The 'V_oy' is simply the original velocity in the vertical or y-direction.
To calculate the position in the y-direction, the full distance formula must be used. 'Y_o', represents the original position in the y-direction.

                                   

Acceleration for projectiles near the Earth's surface is -9.8 m/s². We don't re-write the equation with a negative sign. Rather, we use the negative acceleration value when solving problems.

When a projectile is launched horizontally a ball rolls off a table, a car runs off the edge of a cliff, etc. Here the original y-velocity is zero. For example, if the projectile drops 10 meters, you can set the Yo = 0 and Y_f = -10 m. Or, you can set Yo = 10 m and Y_f = 0. Either works out the same.

Velocity

To determine the total velocity of a projectile, we combine the horizontal velocity
('v_x') and the vertical velocity ('v_y') using the Pythagorean Theorem,

At maximum height

At the top of its path, the projectile no longer is going up and hasn't started down, yet. Its vertical velocity is zero ( v_y = 0 ). The only velocity it has is just its horizontal velocity, vx. Remember, the horizontal speed stays constant throughout the projectile path.

A common misconception occurs at the top of a projectile's arc. When asked what the acceleration of the projectile is at this point, many people answer "zero". If it were zero, the projectile would simply keep going in a straight line. However, gravity is still acting, pulling it down, and accelerating it towards the earth. Thus the acceleration at the top is still -9.8 m/s², just as it's been all along.

Range of projectile motion

For a projectile that is launched at an angle and returns to the same height, we can determine the range or distance it goes horizontally using a fairly simple equation. However, we will focus on the results of studying that equation rather than solving it here.

• When the projectile is launched at a steep angle, it spends more time in the air than it does when launched at a shallow angle.
• When the projectile is launched at a shallow angle, it goes faster in the horizontal direction than if it is launched at a steep angle.

The ideal combination of time in the air and horizontal speed occurs at 45^o. Thus the maximum range or distance occurs when the projectile is launched at this angle. This applies to long jumpers and soccer balls that are two good examples. However, if the projectile starts at a point higher than where it lands, the ideal distance doesn't occur at a 45^o angle. Ask your instructor for an explanation. If you calculate the range for a projectile launched at 30^o, you will find it's the same as a projectile launched at 60^o. The same goes for 40^o and 50^o. The graph of range vs angle is symmetrical around the 45^o maximum.

The equations used to find out various parameters are shown below;

Time of flight,     

Maximum height,     

Horizontal range,  

If the body is projecting from a height “h” above the ground level, the additional height ‘h’ is to be considered and the equations modified accordingly.

  

(c)

The purpose of this experiment is to predict and verify the range and time of flight of a projectile threw at different angles. To find these we it is necessary to know the initial horizontal velocity 'v_x' and the angle of projectile .

Hope this helped for your studies. Keep learning. Have a good day.

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