EARTH SPACE SCIENCE.

a car goes from a velocity zero to a velocity of 15 meters per second East in 2.1 seconds. What is the car's acceleration?

leva [86]

31.5 would be the acceleration.

3 0

3 years ago

Two basketball players are essentially equal in all respects. (They are the same height, they jump with the same initial velocit

ser-zykov [4K]

The reaction time of Boris is t(r), so before that, Boris will not have jumped. Thus, H(b)(t) = 0
The vertical displacement will simply be
D(t) = H(a)(t)

7 0

3 years ago

Calculate the kinetic energy of a 2kg ball moving at 5m/s

shepuryov [24]

Answer:

25

Explanation:

The kinetic energy is 25

8 0

3 years ago

A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.00 m/s at an angle of 20.0

Leya [2.2K]

Explanation :

When a ball is tossed from an upper storey window off a building, the height of the object as a function of time is given by :

$h(t)=ut+\dfrac{1}{2}at^2$

Here, u = 8 m/s

The ball strikes at an angle of 20 degrees below the horizontal. We need to find the time taken by the ball to reach a point 10 meters below the level of launching such that, h (t) = 10 m and a = g = 9.8

$10=ucos(20)t+\dfrac{1}{2}\times 9.8\times (t)^2$

$10=0.93\times 8t+4.9t^2$

$10=7.51t+4.9t^2$

After solving the above equation, t = 0.855 seconds

So, the ball will take 0.855 seconds to reach a point 10 m below the level of launching. Hence, this is the required solution.

3 0

3 years ago

A circuit consists of a coil that has a self-inductance equal to 4.3 mH and an internal resistance equal to 16 Ω, an ideal 9 V b

fredd [130]

Answer:

t = 186.2 μs

Explanation:

Current in LR series circuit

$I(t) = I_{s}( 1 - e^{-Rt/L)}$ ----(1)

steady current = I_{s} = V/R

time constant = τ = $L/R =4.3 * 10^{-3} / 16\\$

= 0.268 ms

magnetic energy stored in coil = $U_{L} = \frac{1}{2}LI^{2}$

rate at which magnetic energy stored in coil= $\frac{d}{dt}U_{L} =\frac{d}{dt} \frac{1}{2}LI^{2} \\ = LI\frac{dI}{dt}\\$ ----(2)

rate at which power is dissipated in R:

$P = I^{2}R$ ---(3)

To find the time when the rate at which energy is dissipated in the coil equals the rate at which magnetic energy is stored in the coil equate (2) and (3)

$I^{2}R=LI \frac{dI}{dt}$