Let's solve each problem step by step using
Newton’s Second Law of Motion, which is:
>
F = m × a
> Where:
> -
F = Force (in Newtons, N)
> -
m = mass (in kilograms, kg)
> -
a = acceleration (in m/s²)
We'll use the triangle method shown in the image:
```
F
/ \
m a
```
- To find
F: multiply m and a → F = m × a
- To find
m: divide F by a → m = F / a
- To find
a: divide F by m → a = F / m
---
1. How much force is needed to accelerate a 1000-kg car at a rate of 3 m/s²?
Given:
- m = 1000 kg
- a = 3 m/s²
Use:
F = m × a
F = 1000 × 3 =
3000 N
✔ Answer: 3000 Units:
N
---
2. If a 70-kg swimmer pushes a pool wall with a force of 250 N, at what rate will the swimmer accelerate from the wall?
Given:
- m = 70 kg
- F = 250 N
Use:
a = F / m
a = 250 / 70 ≈ 3.5714... → Round to 2 decimals:
3.57 m/s²
✔ Answer: 3.57 Units:
m/s²
---
3. A weightlifter raises a 200-kg barbell with an acceleration of 3 m/s². How much force does the weightlifter use to raise the barbell?
Given:
- m = 200 kg
- a = 3 m/s²
Use:
F = m × a
F = 200 × 3 =
600 N
✔ Answer: 600 Units:
N
---
4. A dancer lifts his partner above his head with an acceleration of 2.5 m/s². The dancer exerts a force of 200 N. What is the mass of the partner?
Given:
- F = 200 N
- a = 2.5 m/s²
Use:
m = F / a
m = 200 / 2.5 =
80 kg
✔ Answer: 80 Units:
kg
---
5. Newton’s second law of motion states that a(n) ________ force acting on an object causes it to accelerate according to the formula net force = mass × acceleration. Which means the acceleration of the object is directly proportional to the ________ and inversely proportional to the mass.
Fill in the blanks:
- First blank:
unbalanced → Only unbalanced forces cause acceleration.
- Second blank:
force → Acceleration is directly proportional to force.
✔ Answer:
- "a(n)
unbalanced force"
- "directly proportional to the
force"
---
6. The two factors that affect acceleration are:
From the options:
mass, speed, distance, force, weight
Acceleration depends on:
-
Force (directly proportional)
-
Mass (inversely proportional)
So correct answer:
mass and force
✔ Answer: mass, force
---
7. Friction:
a. Is
static friction when an object is not moving.
→ Static friction prevents motion.
b. Is
sliding friction when two objects rub against each other.
→ Sliding friction occurs during motion.
i.
Fluid friction → a special type of sliding friction when the object slides through a liquid or gas.
c. Is
rolling friction when the object rolls over another.
✔ Answers:
- a.
static friction
- b.
sliding friction
- i.
fluid friction
- c.
rolling friction
---
✔ Final Answers Summary:
1.
3000 N
2.
3.57 m/s²
3.
600 N
4.
80 kg
5.
unbalanced,
force
6.
mass, force
7.
a.
static friction
b.
sliding friction
i.
fluid friction
c.
rolling friction
Let me know if you'd like this formatted as a printable worksheet!
Parent Tip: Review the logic above to help your child master the concept of newton s second law of motion problems worksheet.
