Answer:
a= - 6.667 m/s²
Explanation:
Given that
The initial speed of the box ,u= 20 m/s
The final speed of the box ,v= 0 m/s
The distance cover by box ,s= 30 m
Lets take the acceleration of the box = a
We know that
v²= u ² + 2 a s
Now by putting the values in the above equation we get
0²=20² + 2 a x 30
a= - 6.667 m/s²
Negative sign indicates that velocity and acceleration are in opposite direction.
Therefore the acceleration of the box will be - 6.667 m/s² .
Answer:
Speed of cart's might be less than the high speed after 5 seconds.
Explanation:
Given that,
A fan cart with the fan set to high rolled across the floor.
Let the speed of fan cart with set to high is per second.
The fan supplies a force to the cart. If a lower fan speed were used, less force would be applied. This would cause a slower change in the cart's speed. So, the cart would be rolling more slowly than per second after 5 seconds. The speed of cart's might be less than
per second.
Force is needed
A. for a moving object to keep moving at the same speed and direction
B. for a moving object to change its speed
C. for a motionless object to remain still
D. to prevent a moving object from turning
Hence,
Speed of cart's might be less than the high speed after 5 seconds.
Answer:
T= 1 s
Explanation:
Given that
When x= cm ,T= 1
we know that time period of spring mas system given as
T= Time period
m= mass
k=spring constant
So from above equation we can say that time period of system does not depends on the value of x.
So when x= 10 cm ,still time period will be 1 s.
T= 1 s
Answer:
70 m.
Explanation:
Given,
Frequency, f = 20 HZ
speed of sound, v = 1400 m/s
wavelength of the waves = ?
we know,
v = f λ
Hence, the wavelength of the wave is equal to 70 m.