............................................................................... Hello wonderful person <3
Answer:
<h2>B. 20°</h2>
Explanation:
Range in projectile is defined as the distance covered in the horizontal direction. It is expressed as R = U²sin2Ф/g
U is the initial velocity of the body (in m/s)
Ф is the angle of projection
g is the acceleration due to gravity.
Given U = 14m/s, g = 9.8m/s and range R = 15 m
we will substitute this value into the formula to get the projection angle Ф as shown;
15 = 15²sin2Ф/9.8
15*9.8 = 15²sin2Ф
147 = 225sin2Ф
sin2Ф = 147/225
sin2Ф = 0.6533
2Ф = sin⁻¹0.6533
2Ф = 40.79°
Ф = 40.79°/2
Ф = 20.39° ≈ 20°
Hence, the range is greatest at angle 20°
Answer:
Li has less mass and therefore less inertia, so he can change his motion more easily than Raj.
Explanation:
Inertia describes the resistance of an object to any change in its state of motion, and it depends on the mass of the object only. In particular:
- if an object has a large inertia (large mass), then it is more difficult to change its state of motion (i.e. to put it in motion, or to slow it down, or to change its direction of motion)
- if an object has small inertia (small mass), then it is more easy to change its state of motion
In this problem, Li has less mass than Raj, so he has less inertia, therefore he can change his motion more easily than Raj.
Answer:
1) 
from the positive x-axis.
2) 
Explanation:
Given:
speed of rowing in still water, 
1)
speed of water stream, 
we know that the direction of resultant of the two vectors is given by:
where:
the angle of resultant vector from the positive x-axis.
angle between the given vectors
When the rower wants to reach at the opposite end then:
so,
from the positive x-axis.
2)
Now the resultant velocity of rowing in the stream:
Therefore time taken to cross a 4 miles wide river:
speed increases with temp maybe
