Answer:
679.2 m/s
Explanation:
The formula for the time of flight of a projectile is given as,
T = 2usinФ/g ......................... Equation 1
Where T = Time of flight, u = initial velocity, Ф = angle of projectile to the horizontal, g = acceleration due to gravity.
make u the subject of the equation
u = Tg/2sinФ....................... Equation 2
Given: T = 69 s, Ф = 30°
Constant: g = 9.8 m/s²
Substitute into equation 2
u = (69×9.8)/(2×sin30)
u = 679.2 m/s.
Hence the initial speed of the projectile is 679.2 m/s
Answer:
A. f = 8 Hz
B. T = 0.125 s
C. λ = 0.0166 m = 16.6 mm
D. d = 7.98 m
Explanation:
A.
The frequency of the wave can be given as:
<u>f = 8 Hz</u>
B.
The time period will be:
<u>T = 0.125 s</u>
C.
The wavelength is given as:
<u>λ = 0.0166 m = 16.6 mm</u>
D.
The distance traveled in 1 minute can be found out as follows:
<u>d = 7.98 m</u>
Answer:82. Since you have a distance and a force, then the easiest principle to use is energy, i.e. work.
The work done by friction is F * d. This work cancels out the kinetic energy of the stone (1/2)mv^2
Fd = (1/2)mv^2
F = (1/2)mv^2/d.
Plug in m = 20 kg, v = 3 m/sec, d = 40 m.
83. With more mass, the kinetic energy is higher now. The work needed is higher. W = F * d and F is the same.
Explanation:Hope I helped :)
Answer:
3 m/s²
Explanation:
Sum of forces in the x direction:
∑F = ma
68 N − 23 N = (15 kg) a
a = 3 m/s²