a) Let's call x the direction parallel to the river and y the direction perpendicular to the river.
Dave's velocity of 4.0 m/s corresponds to the velocity along y (across the river), while 6.0 m/s corresponds to the velocity of the boat along x. Therefore, the drection of Dave's boat is given by:
relative to the direction of the river.
b) The distance Dave has to travel it S=360 m, along the y direction. Since the velocity along y is constant (4.0 m/s), this is a uniform motion, so the time taken to cross the river is given by
c) The boat takes 90 s in total to cross the river. The displacement along the y-direction, during this time, is 360 m. The displacement along the x-direction is
so, Dave's landing point is 540 m downstream.
d) If there were no current, Dave would still take 90 seconds to cross the river, because its velocity on the y-axis (4.0 m/s) does not change, so the problem would be solved exactly as done at point b).
That is because work requires energy. According to the law of conservation of energy, it cannot be created or destroyed. When doing work, energy change forms and gets transferred to the object until it is released.
for example, when you lift up an object and place it on a higher elevation, you transferred energy to it and gave it potential energy. The potential energy is transformed into kinetic energy when the object falls down, and if it hits a surface, the energy will scatter, vibrating the areas around it and producing sound.
Also, work= force X distance. The energy does not go away, but rather get changed into some other form of energy
#1
Since Beth rode the Flying saucer ride which is spinning on its axis while axis is moving to and fro as well, so here Beth will experience two motions in this case
(i) Spinning motion
(ii) Rotational motion
#2
Jill and Scott both traveled for 30 min
So time of motion for both is 0.5 h as we know that 1 h = 60 min
Now from the formula of speed we know that
Speed of Jill
speed of Scott
so correct answer is
B) Scott had the faster speed since he rode at 20 k/h while Jill only traveled 10 km/h.
#3
Since we know that <em>acceleration is rate of change in velocity</em>
So here we can say that every motion where velocity changes with time then it is an accelerated motion.
Now change in velocity occurs when either the magnitude will change or its direction will change because here velocity is a vector quantity and it will change with magnitude and direction both.
so here due to oval path the direction of velocity will changes at many points and hence it will be an accelerated motion.
so correct answer is
<em>C) James was right since the car changed direction during the race.</em>
Answer:
I believe it's frictional force
800 J since watts is a measurement of joules per second
