Answer:
The speed of the object is (
)m/s
The magnitude of the acceleration is 4.00m/s²
Explanation:
Given - position vector;
r = (2.0 + 3.00t)i + (3.0 - 2.00t²)j -------------------(i)
To get the speed vector (
), take the first derivative of equation (i) with respect to time t as follows;
= 
= ![\frac{d[(2.0 + 3.00t)i + (3.0 - 2.00t^2)j] }{dt}](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5B%282.0%20%2B%203.00t%29i%20%2B%20%283.0%20-%202.00t%5E2%29j%5D%20%20%7D%7Bdt%7D)
= ------------------------(ii)
To get the acceleration vector (
), take the first derivative of the speed vector in equation(ii) as follows;
j
The magnitude of the acceleration |a| is therefore given by
|a| = |-4.00|
|a| = 4.00 m/s²
In conclusion;
the speed of the object is ()m/s
the magnitude of the acceleration is 4.00m/s²
<span>When a person lifts the block, the block has more potential energy. Therefore the person does positive work on the block.
work = m g h
work = (4.5 kg) (9.80 m/s^2) (1.2 m)
work = 52.92 joules
The person's work on the block is 52.92 joules
When the block is being raised, the force of gravity opposes the motion. Therefore the force of gravity does negative work on the block.
work = - (force) (h)
work = - m g h
work = -(4.5 kg) (9.80 m/s^2) (1.2 m)
work = -52.92 joules
The work done by the force of gravity on the block is -52.92 joules
Note that when the block is moved horizontally, the potential energy does not change. Therefore there is no work done on the block when it moves horizontally (we are assuming that the kinetic energy does not change).</span>
The scientists that study the forces and shape of the earth is called geologist.
Answer:
28.79%
Explanation:
Given
Design Speed, V = 120km/h = 33.33m/s
Radius, R = 300m
Side Friction, Fs = 0.09
Gravitational Constant = 9.8m/s²
Using the following formula, we'll solve the required rate of superelevation.
e + Fs = V²/gR where e = rate
e = V²/gR - Fs
e = (33.33)²/(9.8 * 300) - 0.09
e = 0.287853367346938
e = 28.79%
Hence, the required rate of superelevation for the curve is calculated as 28.79%
