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D. Not recovery devices. In contrast, the other options—A. The body tube, B. The nose cone, and C. The fin—are all essential components of a model rocket. Recovery devices (like parachutes or streamers) are also important for ensuring a safe landing, but "not recovery devices" are not a specific part of the rocket itself.

(a) The uses of polar satellites include: (i) for location identification (ii) to collect data on climate change (iii) observe and predict a natural disaster (iv) use for communication. (b) The slope of a graph of tensile stress against tensile strain represents the modulus of elasticity, also known as Young's modulus. Young's modulus quantifies the stiffness of a material. A steeper slope indicates a stiffer material, while a flatter slope indicates a more flexible material.

Streaming refers to the streamlined shape of an object, which helps minimize air resistance (drag) as it moves through the air. This is often applied in aerodynamics to improve the efficiency of vehicles and objects moving through air.

W\(_{moon}\) = mass x g = mass x \(\frac{10}{6}\) = \(\frac{10m}{6}\)N W\(_{earth}\) = mass x g = mass x 10 = 10m mass = constant g on earth = 10m/s\(^2\) and g on moon = \(\frac{1}{6}\) x that on earth Therefore, The weight of a bowling ball on the moon would be \(\frac{1}{6}\), the weight on earth.

Angular velocity(\(\omega\)) = 2\(\pi\) x rev per sec Rev. per sec = \(\frac{800}{60}\) \(\approxeq\) 13.33 rev/s Angular velocity(\(\omega\)) = 2\(\pi\) x 13.33 \(\approxeq\) 26.7\(\pi\)rad/s

The tangential force acting on an object that prevents it from sliding freely on the adjacent surface is called friction. Friction plays a crucial role in preventing or resisting motion between surfaces in contact.

Effective horizontal force = 15N T = tension on the rope F\(_x\) = T sin\(\theta\) 15 = T x sin 30º T = \(\frac{15}{0.5}\) = 15 x 2 = 30N.

Work is done when a force causes an object to move in the direction of that force. OPTION C. A boy climbs onto a table. Work done (force is applied to lift himself). when a boy climbs onto a table, he exerts a force to lift his body against gravity. As he moves upward, he is doing work because there is a displacement in the direction of the applied force. Thus, work is done in this case.

The energy in a moving car is an example of kinetic energy which is the energy possessed by a body in motion.

The effective force pushing it forward is the horizontal component of the force = F\(_x\) = F Cos\(\theta\) F\(_x\) = F Cos\(\theta\) = 50 x Cos 60º = 50 x 0.5 = 25N

At the maximum height, all the kinetic energy will have been converted into potential energy: mgh = \(\frac{1}{2}\)mv\(^2\) v = y gh = \(\frac{1}{2}\)y\(^2\) h = \(\frac{y^2}{2g}\) Thus, the potential energy will be maximum at the height given by: \(\frac{y^2}{2g}\)

Efficiency = \(\frac{\text{ M.A}}{\text{V.R}}\) x 100 M.A = \(\frac{\text{LOAD}}{\text{EFFORT}}\) V.R = 2, Eff. = 60% = 0.6, Load = 300N 0.6 = \(\frac{\text{M.A}}{2}\) M.A = 1.2 1.2 = \(\frac{300}{\text{E}}\) Effort = \(\frac{300}{1.2}\) = 250N

The velocity ratio of a machine is 4 simply means that the distance moved by effort is 4 times the distance moved by the load.

Mechanical Advantage = \(\frac{\text{load}}{\text{effort}}\) Given: mass(m) = 60kg, acceleration due to gravity(g) = 10ms\(^2\) and effort = 40N Load = m x g = 60 x 10 = 600N M.A = \(\frac{600}{40}\) = 15

Velocity ratio of an inclined plane = \(\frac{1}{Sin\theta}\) = \(\frac{1}{Sin 60}\) ≈ 1.155