I have thrown a ball during gym.
i have knocked my water bottle off my desk
i have opened a door.
Answer:
a) 30 degree
Explanation:
As we know that time of flight of the projectile depends on the the vertical component of the velocity always
It is given as

now we know that

so we will have

since we know that two projectiles are projected at same speed but different angles
so smaller the angle will take smaller time
so it would be 30 degree projectile which will take smaller time
Answer:
7.89 7.91
Explanation:
The ranges of measurement lie between 7.92-0.05 and 7.92+0.05
7.87g and 7.97g
Answer:
0.47 J
Explanation:
The elastic potential energy of a spring is given as,
E = 1/2ke²........................ Equation 1
Where E = Elastic potential energy, k = spring constant, e = extension/compression.
Given: k = 15 N/m, e = 0.25 m.
Substitute into equation 1.
E = 1/2(15)(0.25)²
E = 0.46875
E ≈ 0.47 J.
Hence the elastic potential energy stored in the spring = 0.47 J