Answer:
Explanation:
mass, m = 1 kg
Position (2, 3 ) m
height, h = 2 m
acceleration due to gravity, g = 9.8 m/s^2
Here, no force is acting in horizontal direction, the force of gravity is acting in vertical direction, so the work done by the gravitational force is to be calculated.
Force mass x acceleration due to gravity
F = 1 x 9.8 = 9.8 N
Work = force x displacement x CosФ
Where, Ф be the angle between force vector and the displacement vector.
Here the value of Ф is 180° as the force acting vertically downward and the displacement is upward
So, W = 9.8 x 2 x Cos 180°
W = - 19.6 J
Thus, option (A) is correct.
Answer:
72.98 km
Explanation:
Her displacement is simply the distance from her final position to her initial position.
Now, I've drawn and attached a triangle diagram to depict this her movement.
Point O is her initial starting point.
Point A is the first point she gets to after travelling north while point B is the final point after travelling north east.
From the triangle, the displacement will be the distance OB which is denoted by x and can be solved from cosine rule.
Thus;
x² = 62² + 26² - 2(62 × 26)cos 120
x² = 4520 + 806
x² = 5326
x = √5326
x = 72.98 km
Correct answer choice is:
D. A frequency higher than the original frequency.
Explanation:
This is a true case of Doppler's effect. The Doppler effect can be defined as the effect originated by a traveling source of waves in which there is a visible higher variation in pulse for observers towards what the source is progressing and a visible descending shift in rate for observers from what the source is dropping.
Answer:
Part a)
Part b)
T = 4.68 s
Explanation:
Part a)
Shell is fired at speed of 40 m/s at angle of 35 degree
so here we have
since gravity act opposite to vertical speed of the shell so at the highest point of its trajectory the vertical component of the speed will become zero
so at the highest point the speed is given
Part b)
After completing the motion we know that the displacement of the object will be zero in Y direction
so we have
Answer:
Conductors have magnetic fields; insulators do not have magnetic fields. Conductors do not have magnetic fields; insulators do have magnetic fields. ... In a conductor, electric current cannot flow freely; in an insulator, it can flow freely.
