Answer:
The maximum height reached by the body is 313.6 m
The time to return to its point of projection is 8 s.
Explanation:
Given;
initial velocity of the body, u = 78.4 m/s
at maximum height (h) the final velocity of the body (v) = 0
The following equation is applied to determine the maximum height reached by the body;
v² = u² - 2gh
0 = u² - 2gh
2gh = u²
h = u²/2g
h = (78.4²) / (2 x 9.8)
h = 313.6 m
The time to return to its point of projection is calculated as follows;
at maximum height, the final velocity becomes the initial velocity = 0
h = v + ¹/₂gt²
h = 0 + ¹/₂gt²
h = ¹/₂gt²
2h = gt²
t² = 2h/g
Answer:
The right solution is "2.5 m/s²". A further explanation is given below.
Explanation:
The given values are:
Initial velocity,
= 20 m/s
Final velocity,
= 0 m/s
Time,
= 8 s
As we know,
⇒ 
On substituting the values, we get
⇒ 
⇒ 
⇒ 
Answer:
The wall is 680 meter away from the person.
Explanation:
Given data
Speed of sound = 340 
Given that Persons said hello toward the opposite side she has an echo hello 4 seconds later means it takes 2 seconds for the sound to reach the wall & again 2 seconds to reach the persons ear.
Therefore the distance between the person & wall is
D = speed × Time
D = 340 × 2
D = 680 meter
Therefore the wall is 680 meter away from the person.
Explanation:
Impulse = change in momentum
FΔt = Δp
(53 N) (15 s) = Δp
Δp = 795 kg m/s
For constant mass:
Δp = m Δv
795 kg m/s = (12 kg) Δv
Δv = 66.25 m/s
Rounding to two significant figures, Δp = 800 kg m/s and Δv = 66 m/s.
Wat does that mean I don't understand this
