Answer:
a. 8.96 m/s b. 1.81 m
Explanation:
Here is the complete question.
a) A long jumper leaves the ground at 45° above the horizontal and lands 8.2 m away.
What is her "takeoff" speed v
0
?
b) Now she is out on a hike and comes to the left bank of a river. There is no bridge and the right bank is 10.0 m away horizontally and 2.5 m, vertically below.
If she long jumps from the edge of the left bank at 45° with the speed calculated in part a), how long, or short, of the opposite bank will she land?
a. Since she lands 8.2 m away and leaves at an angle of 45 above the horizontal, this is a case of projectile motion. We calculate the takeoff speed v₀ from R = v₀²sin2θ/g. where R = range = 8.2 m.
So, v₀ = √gR/sin2θ = √9.8 × 8.2/sin(2×45) = √80.36/sin90 = √80.36 = 8.96 m/s.
b. We use R = v₀²sin2θ/g to calculate how long or short of the opposite bank she will land. With v₀ = 8.96 m/s and θ = 45
R = 8.96²sin(2 × 45)/9.8 = 80.2816/9.8 = 8.192 m.
So she land 8.192 m away from her bank. The distance away from the opposite bank she lands is 10 - 8.192 m = 1.808 m ≅ 1.81 m
The correct answer to the question is : D) 352.6 m/s.
CALCULATION :
As per the question, the temperature is increased from 30 degree celsius to 36 degree celsius.
We are asked to calculate the velocity of sound at 36 degree celsius.
Velocity of sound is dependent on temperature. More is the temperature, more is velocity of sound.
The velocity at this temperature is calculated as -
V = 331 + 0.6T m/s
= 331 + 0.6 × 36 m/s
= 331 + 21.6 m/s
= 352.6 m/s.
Here, T denotes the temperature of the surrounding.
Hence, velocity of the sound will be 352.6 m/s.
The answer to this question is A - 25 N
