Answer:
A. Acceleration always involves changing speed.
Explanation:
Acceleration is defined as the rate of change of velocity.
Velocity is a vector quantity and is defined as speed in a given direction. Therefore, when any or both of the components of velocity is changing with time, a body is said to be accelerating i.e. acceleration involves a change of speed or change in direction, or a change in both speed and direction.
Considering the statements:
A. Acceleration always involves changing speed is false because acceleration can occur when speed is constant but direction is changing.
B. Changing direction always involves acceleration is true because, a change in direction results in a change in velocity.
C Changing speed always involves acceleration is true because, changing speed results in a change in velocity.
D. Circular motion always involves acceleration is true because in circular motion the direction is always changing, and this results in a change in velocity
Answer:
<em>The force that would be applied on the rope just to start moving the wagon is 122 N</em>
Explanation:
Frictional force opposes motion between two surfaces in contact. It is the force that must be applied before a body starts to move. Static friction opposes the motion of two bodies that are in contact but are not moving. The magnitude of static friction to overcome for the body to move can be calculated using equation 1.
F = μ x mg .............................. 1
where F is the frictional force;
μ is the coefficient of friction ( μs, in this case, static friction);
m is mass of the object and;
g is the acceleration due to gravity( a constant equal to 9.81 m/
)
from the equation we are provide with;
μs = 0.25
m = 50 kg
g = 9.81 m/
F =?
Using equation 1
F = 0.25 x 50 kg x 9.81 m/
F = 122.63 N
<em>Therefore a force of 122 N must be applied to the rope just to start the wagon.</em>
C.Earth is the largest and most dense of the terrestrial planets
Answer:
<h2>98 J</h2>
Explanation:
The potential energy of a body can be found by using the formula
PE = mgh
where
m is the mass
h is the height
g is the acceleration due to gravity which is 9.8 m/s²
From the question we have
PE = 5 × 9.8 × 2
We have the final answer as
<h3>98 J</h3>
Hope this helps you
