Answer:
The work done by the child as the tricycle travels down the incline is 416.96 J
Explanation:
Given;
initial velocity of the child, = 1.4 m/s
final velocity of the child, = 6.5 m/s
initial height of the inclined plane, h = 2.25 m
length of the inclined plane, L = 12.4 m
total mass, m = 48 kg
frictional force, = 41 N
The work done by the child is calculated as;
Therefore, the work done by the child as the tricycle travels down the incline is 416.96 J
This question is incomplete, the complete question is;
Two plane mirrors intersect at right angles. A laser beam strikes the first of them at a point 11.5 cm from their point of intersection, as shown in the figure.
For what angle of incidence at the first mirror will this ray strike the midpoint of the second mirror (which is 28.0 cmcm long) after reflecting from the first mirror
Answer: angle of incidence is 39.4°
Explanation:
Given that;
two plain mirrors intersect at right angle (90°)
distance d = 11.5 cm
S = 28.0 cm
Now the angle that the reflection ray males with first the mirror equal theta (∅)
so
tan∅ = (S/2) / d
tan∅ = (28/2) / 11.5
tan∅ = 14 / 11.5
tan∅ = 1.2173
∅ = tan⁻¹ (1.2173)
∅ = 50.6°
so angle of incidence = 90° - ∅
= 90° - 50.6°
= 39.4°
Therefore angle of incidence is 39.4°
Answer:
B. x - t graph
Explanation:
A position-time (x-t) graph is a graph of the position of an object against (versus) time.
Generally, the slope of the line of a position-time (x-t) graph is typically used to determine or calculate the velocity of an object.
An instantaneous velocity can be defined as the rate of change in position of an object in motion for a short-specified interval of time. Thus, an instantaneous velocity is a quantity that can be found by measuring the slope of a line that is tangent to a point on the graph.
Hence, the x - t graph also referred to as the position-time graph is used for determining the instantaneous velocity from the slope.
<u>For example;</u>
Given that the equation of motion is S(t) = 4t² + 2t + 10. Find the instantaneous velocity at t = 5 seconds.
Solution.
Differentiating the equation, we have;
Substituting the value of "t" into the equation, we have;
S(5) = 42 m/s.
The velocity of the current in a river has no effect on the the time it takes to paddle a canoe across the river, given that the boat is pointed perpendicular to the bank of the river, because
The velocity of the river does not change the velocity and therefore the distance traveled in the direction of the boat which is directed perpendicular to it
Reason:
Let represent the velocity of the boat across the river in the direction,
, and let,
, represent the velocity of the river, we have;
The velocity of the boat perpendicular to the direction of the river =
Therefore, the distance covered per unit time in the perpendicular direction
to the flow of the river is , such that the time it takes to cross the river in
the perpendicular direction is the same, for every value of the velocity of
the river.
This is so because the velocity in the perpendicular direction to the flow of
the river, which is the velocity of the boat is unchanged by the velocity of
the river, because there is no perpendicular component of velocity in the
velocity of the river.
= 3 m/s
= 4 m/s
The width of the river, = 6 meters, we have;
The direction, θ, is given as follows;
The length of the path of the boat, <em>l</em>, is given as follows;
The length of the path the boat takes = 10 m
The time it takes to cross the river, t = , therefore;
Considering only the y-components, we have;
Therefore;
Which expresses that the time taken is the same and given that the
vectors of the velocities of the river and the boat are perpendicular, the
distance covered in the direction of the boat is unaffected by the velocity
of the river.
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