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If a ball rolls off the edge of a table two meters above the floor and with an initial velocity of 20 meters per second what is the ball's acceleration and velocity just before it hits the ground?
Wiki User
ā 16y ago
The horizontal velocity has no bearing on the time it takes for the ball to fall to the floor and, ignoring the effects of air resistance, will not change throughout the ball's fall, so you know Vx. The vertical velocity right before impact is easily calculated using the standard formula: d - d0 = V0t + [1/2]at2. For this problem, let's assume the floor represents zero height, so the initial height, d0, is 2. Further, substitute -g for a and assume an initial vertical velocity of zero, which changes our equation to 0 - 2 = 0t - [1/2]gt2. Now, solve for t. That gives you the time it takes for the ball to hit the floor. If you divide the distance traveled by that time, you know the average vertical velocity of the ball. Double that, and you have the final vertical velocity! (Do you know why?) Now do the vector addition of the vertical velocity and the horizontal velocity. Remember, the vertical velocity is negative!
Wiki User
ā 16y ago
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How long does it take to hit the ground from 28000 feet high?
The answer will depend on what "it" is, and on what its initial velocity is.
Will a ball drop rest reach the ground quicker than the one lunched from the same height but with and initial horizontal velocity?
No. What counts in this case is the vertical component of the velocity, and the initial vertical velocity is zero, one way or another.
An arrow is shot straight up at an initial velocity of 250ms How long will it take to hit the ground?
This is a velocity question so u need to use uvaxt
If the velocity of a particle is nonzero can the particle's acceleration be zero?
yes. If the forces acting on the a moving particle are in equilibrium, (e.g. when a spherical object reaches terminal velocity (neglecting increased air resistance as it gets closer to the ground)) then the particle will be moving at a velocity, that is not 0, yet the velocity will remain constant, and the body will not accelerate or decelerate in any direction, and thus the acceleration is 0.
What speed must an object leave the ground to travel 2.5 meters up?
Using the physics formula: v2 = u2 + 2as v - final velocity u - initial velocity a - acceleration s - distance When the object leaves the ground it is being slowed down by gravity until it stops so the acceleration equals -9.8m/s2 and as it will stop at 2.5 meters v = 0. U is the value we want to find out: 02 = u2 + (2 *-9.8*2.5) 49 = u2 So the object must leave the ground at 7m/s. By the way this is ignoring air resistance.
An apple falls from a tree and reaches the ground in 4 seconds with a velocity of 40m/s. What is the acceleration?
Using the acceleration formula, final acceleration is the final velocity minus the initial velocity over elapsed time. Final velocity you gave as 40m/s, and the initial velocity was zero (the apple was stationary on the tree), so the difference is 40 m/s. Divided by the time you gave, 4 s, this will be 10 m/sĀ²
Why velocity is non zero when ball dropped to the ground?
The initial velocity of a dropped ball is zero in the y (up-down) direction. After it is dropped gravity causes an acceleration, which causes the velocity to increase. F = ma, The acceleration due to gravity creates a force on the mass of the ball.
Why that the slowing down of moving object is considered to be a form of acceleration?
Acceleration is defined by physics as the rate of change of velocity over time. a = dv/dt As time changes, any change in velocity results in a change in acceleration. That change can be positive or negative. If you want to know why, its because acceleration and velocity are vectors. A vector has a magnitude and a direction. The magnitude is the value, and the direction refers to the direction the object is traveling. An example when acceleration doesn't point in the same direction as velocity is when you throw a ball into the air. You throw it up, so the initial velocity is in the upward direction. However the acceleration due to gravity is downward. It will slowly decrease the upward velocity of the ball until it is zero. At that point the ball will start to fall downard and increase in velocity until it hits the ground.
A skydiver steps from a helicopter and falls for 5 seconds before reaching her terminal velocity during this 5 second interval her acceleration?
the crate will reach terminal velocity last, but hit the ground frist.
Calculate the velocity of ball just before it hits the ground when dropped from a height of 6m?
Here are two different methods to solve this kind of problem. 1) Use one of the formulae for constant acceleration. In this case, vf2 = vi2 + 2as, where vf is the final velocity, vi is the initial velocity (zero in this case), a is the acceleration (9.8 meters / second2), and s is the distance. 2) Do an energy calculation, as follows: Calculate the potential energy at a height of 6 meters, with the formula PE = mgh. Since we can assume that the entire potential energy gets converted to kinetic energy just before the ball hits the ground, solve for velocity, in the kinetic energy formula.
What is A football kicked off at an angle 20 from the ground reaches a maximum height of 4.7 m What is the initial velocity of the kick?
initial velocity of the kick = 28.06 m/s
Which information is needed to find the time a projectile is in motion?
The object's initial distance above the ground The object's initial velocity
If an object is dropped and reaches the ground with a final velocity of 4 meter per second neglecting air friction how far did the object fall?
Use the mechanics formula Final velocity = initial velocity + acceleration * change in time 4m/s = 0 + (9.8 m/s²)t t = 0.41s distance = initial velocity * time + 1/2 accel * time² = 1/2(9.8m/s²)(0.41s)² = 0.82m
How long does it take to hit the ground from 28000 feet high?
The answer will depend on what "it" is, and on what its initial velocity is.
Do you agree with the statement an object with a zero velocity can have an acceleration greater than yero?
Of course. Toss a stone straight up. -- From the moment it leaves your hand until the moment it hits the ground, it has constant acceleration ... the acceleration of gravity, around 10 meters per second2. The number isn't important, only the fact that the acceleration of the stone is not zero until it hits the ground. -- Velocity-wise: The stone starts out with some upward velocity, which steadily decreases until it's at the top of its arc, then the velocity becomes downward and increases until the stone hits the ground. -- At the very top of the arc, there is a point where the velocity changes from upward to downward. In order for that to happen, there must be an instant when the velocity is zero. -- But the acceleration is constant and not zero, even at that instant when the velocity is zero.
Will a ball drop rest reach the ground quicker than the one lunched from the same height but with and initial horizontal velocity?
No. What counts in this case is the vertical component of the velocity, and the initial vertical velocity is zero, one way or another.
What is the rock's approximate velocity just prior to hitting the ground?
To answer this question one would need to know the rock's initial height and velocity.
