A force of 25N acts on a body at rest for 0.2s and a force of 70N acts for the next 0.1s in opposite direction .If the final velocity of the body is 5ms,the mass of the body is
7 N∙s - 5 N∙s = 2 N∙s
m v = 2 N∙s
m = 2/5 kg
how do you get 7ns-5ns from the question i didn't understand
I don't understand the way you solved the question
To find the mass of the body, we can use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.
First, let's calculate the net force acting on the body during the given time intervals.
In the first time interval of 0.2 seconds, a force of 25N acts on the body. Since the body is at rest initially, we can find the acceleration using the equation:
Force = mass * acceleration
Rearranging the equation, we get:
Acceleration = Force / mass
So, the acceleration during the first time interval is:
a1 = 25N / m (Equation 1)
Next, during the next 0.1 seconds, a force of 70N acts on the body in the opposite direction. Using the same equation as above, we can find the acceleration during this time interval:
a2 = -70N / m (Equation 2)
Now, to find the final velocity of the body, we can use the equation:
Final velocity = Initial velocity + (acceleration * time)
Since the initial velocity is zero (as given in the question) and the final velocity is 5 m/s, the equation becomes:
5 = 0 + (acceleration * 0.3) (0.3 seconds is the total time elapsed: 0.2s + 0.1s)
Simplifying the equation:
5 = 0.3 * acceleration
Therefore, the acceleration is:
acceleration = 5 / 0.3
Now, substitute this value of acceleration into Equation 1 and Equation 2:
a1 = 25N / m (Equation 1)
a2 = -70N / m (Equation 2)
25N / m = 5 / 0.3
To find the value of 'm', we can rearrange the equation as follows:
25N * 0.3 = 5 * m
7.5N = 5m
So, m = 7.5N / 5
m = 1.5 kg
Therefore, the mass of the body is 1.5 kg.