Answer:
Part a)
Part b)
Part c)
Explanation:
Part a)
Object is thrown sideways
since the railroad car is moving on the track so there is no change in the momentum in the direction of motion of the car
so final speed of the car will not change
Part b)
By momentum conservation we can write
Part c)
Again by momentum conservation we have
Answer:
(a) 0.177 m
(b) 16.491 s
(c) 25 cycles
Explanation:
(a)
Distance between the maximum and the minimum of the wave = 2A ............ Equation 1
Where A = amplitude of the wave.
Given: A = 0.0885 m,
Distance between the maximum and the minimum of the wave = (2×0.0885) m
Distance between the maximum and the minimum of the wave = 0.177 m.
(b)
T = 1/f ...................... Equation 2.
Where T = period, f = frequency.
Given: f = 4.31 Hz
T = 1/4.31
T = 0.23 s.
If 1 cycle pass through the stationary observer for 0.23 s.
Then, 71.7 cycles will pass through the stationary observer for (0.23×71.7) s.
= 16.491 s.
(c)
If 1.21 m contains 1 cycle,
Then, 30.7 m will contain (30.7×1)/1.21
= 25.37 cycles
Approximately 25 cycles.
The focal point of a mirror is half of the radius of curvature. We can use the formula, 1/f = 1/v + 1/u where f is the focal length , v is the image distance and u is object distance The distance of the star is assumed to be incredibly far away and 1 divided by a really big number is approximately zero, thus; 1/f = 1/v = 1/75 = 1/v therefore; the image is formed 75 cm infront of the mirror
The table is almost perfect. BUT ... since she called ay negative, that means she's calling the upward direction positive-y and the downward direction negative-y. In that case, since the ball moves downward from the deck to the pavement, the change in y should be negative 3.2 m. Everything else in her table is fine. Choice-D is the good one.
Now, regarding the speed of the ball ...
How long does it take to fall 3.2 m ?
Use the formula. D = 1/2 g T^2 .
3.2 = 4.9 T^2.
T^2 = 3.2/4.9
T = √(3.2/4.9) = 0.808 second.
The ball hit the pavement 0.808 second after it rolled off the deck. So that's also the time it took to move the 0.75 m horizontally.
Speed = distance / time
Speed = 0.75 m / 0.808 second
Speed = 0.928 meter/second .