Answer:
X(t) = 9.8 *t - 4.9 * t^2
Explanation:
We set a frame of reference with origin at the hand of the girl the moment she releases the ball. We assume her hand will be in the same position when she catches it again. The positive X axis point upwards.The ball will be subject to a constant gravitational acceleration of -9.81 m/s^2.
We use the equation for position under constant acceleration:
X(t) = X0 + V0 * t + 1/2 * a *t^2
X0 = 0 because it is at the origin of the coordinate system.
We know that at t = 2, the position will be zero.
X(2) = 0 = V0 * 2 + 1/2 * -9.81 * 2^2
0 = 2 * V0 - 4.9 * 4
2 * V0 = 19.6
V0 = 9.8 m/s
Then the position of the ball as a function of time is:
X(t) = 9.8 *t - 4.9 * t^2
According to Lawson's criterion, the outcome is determined by the product of ion density and confinement time because the temperature must be maintained for a sufficient confinement time and with a sufficient ion thickness to obtain a net gain of power from a fusion reaction.
<h3>What are
Lawson's criterion?</h3>
- The overall conditions that must be met in order to produce more energy than is required for plasma heating are usually expressed in terms of the product of ion density and confinement time, a condition known as Lawson's criterion.
- In nuclear fusion devices, confinement time is defined as the amount of time the plasma is kept at a temperature above the critical ignition temperature.
- Even at temperatures high enough to overcome the coulomb barrier to nuclear fusion, a critical density of ions must be maintained in order to achieve a net yield of energy from the reaction.
- Because the density required for a net energy yield is correlated with the confinement time for hot plasma, the minimum condition for a productive fusion reaction is typically stated in terms of the product of ion density and confinement time, which is known as Lawson's criterion.
To learn more about Lawson's criterion, refer:
brainly.com/question/28303495
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To have a weight of 2.21N., the ball's mass is (2.21/9.8) = .226kg.
<span>a) d = 1/2 (vt), = 1/2 (18 x .17), = 1.53m. </span>
<span>b) Acceleration of the ball = (v/t), = 18/.17, = 105.88m/sec^2. </span>
<span>f = (ma), = .226 x 105.88, = 23.92N. </span>
Before you step on the brakes, the car has kinetic energy, when you step on the brakes, it turns the kinetic energy into heat (thermal energy). When it stops completely, it has potential energy. Hope this helped :)
Answer:
KE2 = 2 KE1
1/2 M V2^2 = 2 * (1/2 M V1^2)
V2^2 = 2 V1^2
V2 = V1
Since momentum = M V the momentum increases by
