# Practice on Force and Density: Solution-1

Question 1: As per the figure, find he magnitude of the resultant vector.
• 64
• 66
• 75
• 78
Answer: 78
Explanation: Use Pythagoras theorem where c2 = a 2 + b 2.
So here the c is magnitude of the resultant vector. Hence, c2 = 502 + 602 = 2,500 + 3,600 = 6,100,
and c, the magnitude of the resultant vector = 78.1

Question 2: What will be the direction of the resultant vector in the figure of question 1?

• north east
• north west
• south east
• north west
Answer: north east

Question 3: As per the figure, find the horizontal component of the force.
• 18.8 N
• − 18.8 N
• 19.0
• − 19.0 N
Answer: − 18.8 N
Explanation: the magnitude of horizontal component of the force = cosine(20°)× 20 N = 18.79 N

Question 4: As per the figure mentioned in question 3, find the vertical component of the force.
• 7 N
• − 6.84 N
• 6.84 N
• 9 N
Answer: − 6.84 N

Explanation: the magnitude of vertical component of the force = sine(20°)× 20 N = 6.84 N

Question 5: Assume that a body of mass of 50 g and a volume of 2 cm3.
Find the item's density in kg/m3.

• 27,000 kg/m3
• 25,000 kg/m3
• 25 k/cm3
• 25,000 g/m3
Answer: 25,000 kg/m3
Explanation: density = mass / volume = 50 × 10− 3kg / 2 × 10− 6m3 = 25,000 kg/m3

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Date of last modification: Summer , 2019