Answer:
The statement is not correct.
Explanation:
To know if the statement is correct, we shall determine the velocity of the car after 3 s. This is illustrated below.
Data obtained from the question include:
Initial velocity (u) = 0 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) = 3 s
Final velocity (v) =?
v = u + gt
v = 0 + (9.8 × 3)
v = 0 + 29.4
v = 29.4 m/s
Thus, the velocity of the car after 3 s is 29.4 m/s.
Hence, the statement made by the friend is not correct as the car has a falling velocity of 29.4 m/s after 3 s.
Answer
given,
v = 128 ft/s
angle made with horizontal = 30°
now,
horizontal component of velocity
vx = v cos θ = 128 x cos 30° = 110.85 ft/s
vertical component of velocity
vy = v sin θ = 128 x sin 30° = 64 m/s
time taken to strike the ground
using equation of motion
v = u + at
0 =-64 -32 x t
t = 2 s
total time of flight is equal to
T = 2 t = 2 x 2 = 4 s
b) maximum height
using equation of motion
v² = u² + 2 a h
0 = 64² - 2 x 32 x h
64 h = 64²
h = 64 ft
c) range
R = v_x × time of flight
R = 110.85 × 4
R = 443.4 ft
Answer:
An electric generator is a device that converts a form of energy into electricity.
Explanation:
The recoil velocity of cannon is (4) 5.0 m/s
Explanation:
We can find the recoil velocity from the law of conservation of momentum.
The recoil velocity is velocity of body 2 after release of body 1, i.e. velocity of cannon after release of clown.
Let v2 be cannon's velocity, v1 be clown's velocity given = 15 m/sec
m1 be clown's mass = 100kg and m2 be cannon's mass given = 500kg.
So recoil velocity of cannon v2 is given by,
v2 = -(m1÷m2)v1
v2 = -(100÷500)15
v2 = -5 m/s
where the minus sign refers to the direction of cannon's recoil velocity being opposite to that of clown.
Hence, option (4)5.0 m/s is the correct answer.
