Choice A is correct.======Kinetic energy equation: KE = (1/2)(m)(v²)This tells us that KE is directly proportional to mass and the square of velocity. In other words, the more mass and more velocity an object has, the more kinetic energy.If an object is sitting at the top of a ramp, there is no velocity and therefore no kinetic energy. Choices B and D are wrong.A golf ball has more mass than a ping-pong ball, so a ping-pong ball would have less kinetic energy than a golf ball rolling off the end of a ramp. Choice C is wrong.Choice A is correct.
Formula for height
<span> r(t) = a/2 t² + v₀ t + r₀
</span><span> where
</span><span> a = acceleration = -32 ft/sec² (gravity)
</span><span> v₀ = initial velocity
</span><span> r₀ = initial height
</span><span> r(t) = -16t² + v₀ t + r₀
</span> <span>Tomato passes window (height = 450 ft) after 2 seconds:
</span><span> r(2) = 450
</span><span> -16(4) + v₀ (2) + r₀ = 450
</span><span> r₀ = 450 + 64 - 2v₀
</span><span> r₀ = 514 - 2v₀
</span><span> Tomato hits the ground (height = 0 ft) after 5 seconds:
</span><span> r(5) = 0
</span><span> -16(25) + v₀ (5) + r₀ = 0
</span> r<span>₀ = 16(25) - 5v₀
</span><span> r₀ = 400 - 5v₀
</span><span>
r₀ = 514 - 2v₀ and r₀ = 400 - 5v₀
</span> <span>514 - 2v₀ = 400 - 5v₀
</span><span> 5v₀ - 2v₀ = 400 - 514
</span> <span>3v₀ = −114
</span><span> v₀ = −38
</span><span> Initial velocity = −38 ft/sec (so tomato was thrown down)
</span><span> (initial height = 590 ft) </span>
Answer:
c. The particle is moving in a positive direction, and its speed is decreasing.
Answer:
Frequency=0.39Hz
Explanation:
A pendulum completes 23 full cycles in 58 seconds
A pendulum completes 1 full cycle in 58/23=2.52 seconds
Time taken(t)=2.52 seconds
Now,
Frequency=1/time taken
Frequency=1/2.25
Frequency=0.39Hz
Answer: D (sandy clay loam)
Explanation:
It is because it is 55 percent sand, and 25 percent clay, so it has to be more sandy than silty. Much of it is by sand, so it is sandy. Loam is a fertile soil of clay and sand, so it is D.
