As we know that total work done by a force is given by
so it is product of force and displacement along same direction
as we can write it as
so it must be the product of force and displacement in same directions so correct answer must be
<u>b. is parallel to the displacement of the object</u>
Answer: 75,242.9 m/s
Explanation:
from the question we are given the following parameters
mass of Lion (ML) = 169,169 kg
velocity of lion (VL) = 777,377.7 m/s
mass of Gazelle (Mg) = 31,731.7 kg
velocity of Gazelle (Vg) = 63,863.8 kg
mass of Lion and Gazelle (M) = 200,900.7 kg
velocity of Lion and Gazelle (V) = ?
The first figure below shows the motion of the Lion and Gazelle with their direction.
The second diagram shows the motion of the Lion and Gazelle with their directions rearranged to form a right angle triangle.
from the triangle formed we can get the velocity of the Lion and Gazelle immediately after collision using their momentum and Phytaghoras theorem
momentum = mass x velocity
momentum of the Lion = 169,169 x 77,377.3 = 13,089,840,463.7 kgm/s
momentum of the Gazelle = 31,731.7 x 63,863.8 = 2,026,506,942.46 kgm/s
momentum of the Lion and Gazelle = 200,900.7 x V
now applying Phytaghoras theorem we have
13,089,840,463.7 + 2,026,506,942.46 = 200,900.7 x V
15,116,347,406.16 = 200,900.7 x V
V = 75,242.9 m/s
(a) 29.8 m/s
To solve this problem, we start by analyze the vertical motion first. This is a free fall motion, so we can use the following suvat equation:
where, taking upward as positive direction:
is the final vertical velocity
is the initial vertical velocity (zero because the pebble is launched horizontally)
is the acceleration of gravity
s = -25.0 m is the displacement
Solving for vy,
(downward, so we take the negative solution)
The pebble also have a horizontal component of the velocity, which remains constant during the whole motion, so it is
So, the final speed of the pebble as it strikes the ground is
(b) 29.8 m/s
In this case, the pebble is launched straight up, so its initial vertical velocity is
So we can find the final vertical velocity using the same suvat equation as before:
(downward, so we take the negative solution)
The horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
(c) 29.8 m/s
This case is similarly to the previous one: the only difference here is that the pebble is launched straight down instead than up, therefore
Using again the same suvat equation:
(downward, so we take the negative solution)
As before, the horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
We notice that the final value of the speed is always the same in all the three parts, so it does not depend on the direction of launching. This is due to the law of conservation of energy: in fact, the initial mechanical energy of the pebble (kinetic+potential) is the same in all three cases (because the height h does not change, and the speed v does not change either), and the kinetic energy gained during the fall is also the same (since the pebble falls the same distance in all 3 cases), therefore the final speed must also be the same.