Answer:
5.3Km/hr
Explanation:
Velocity=Displacement/Time
D=4km;T=0.75hr
V=4/0.75=5.33..
A child slides down a hill on a toboggan with acceleration of 1.8 m/s2. if she starts from rest, how far has she traveled in: 2 seconds
Answer:
2.4 m
Explanation:
From the question above,
Applying equation of motion,
s = ut+at²/2....................... Equation 1
Where t = time, u = initial velocity, a = acceleration, s = distance.
make s the subject of the equation,
Given: a = 1.8 m/s², t = 2 seconds, u = 0 m/s (from rest)
Substitute these value into equation 1
s = 0(2)+1.8(2²)/2
s = 1.2(4)/2
s = 2.4 m.
Hence she has traveled 2.4 m
Answer:
False
Explanation:
An object in uniform circular motion must be changing its velocity in order to move in a circular path.
In fact, remind that velocity is a vector which consists of a magnitude (the speed) and a direction.
When an object is moving in uniform circular motion, the direction of the motion is constantly changing (since the trajectory is a circle): so, this means that the velocity is also changing. However, this does not imply that the speed of the object is changing. In fact, in a uniform circular motion, the speed of the object remains constant.
The kinetic energy (KE) of a 0.155 kg arrow that is shot from ground level, upward at 31.4 m/s, when it is 30.0 m above the ground is 30.85 J
Assuming air friction is negligible,
a = - 9.8 m / s²
u = 31.4 m / s
s = 30 m
v² = u² + 2 a s
v² = 31.4² + ( 2 * - 9.8 * 30 )
v² = 985.96 - 588
v² = 397.96 m / s
KE = 1 / 2 m v²
KE = 1 / 2 * 0.155 * 397.96
KE = 0.0775 * 397.96
KE = 30.85 J
Therefore, the kinetic energy ( KE ) when it is 30.0 m above the ground is 30.85 J
To know more about kinetic energy
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